source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-301 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
Humans are | [
"Air",
"Sunlight",
"Water",
"Plants"
] | C | animals require water for survival |
OpenBookQA | OpenBookQA-302 | organic-chemistry, spectroscopy, analytical-chemistry, nmr-spectroscopy
Obviously there is some guess work in here and if it was an important project I'd do some further experiments and look for some additional model compounds in order to confirm these assignments and remove the discrepancies, but this is a good start.
The following is multiple choice question (with options) to answer.
As I search among classifications, its groupings of materials, and properties, I may be looking for | [
"hydrogen peroxide",
"aspirin",
"vitamins",
"petroleum jelly."
] | C | classifying means grouping materials by their properties |
OpenBookQA | OpenBookQA-303 | mobile-robot, quadcopter, microcontroller, mechanism, embedded-systems
Title: Iron man Jarvis like robot I'm very passionate about robots from my childhood.I'm a java developer.
I love sci-fi movies.I have a little bit knowledge in embedded systems and electronics.
My ambition is to build a robot like Jarvis (In Iron Man Movie).Which is a voice controlled robot.I would like to implement that in my house as a home automation system.It would take voice as input and take appropriate action.. Please help me to do this.
Any kind of help is appreciated.. As it has already been pointed out, this is such a broad topic, it's almost impossible to answer it... People do entire doctoral thesis for years on "just" one aspect like speech recognition!!
But here is what you could do:
1) get a Raspberry Pi for the brain. You'll have to learn how to use Linux and a programming language like Python
2) get a cheap robotic arm: this one has been reverse-engineered before and you can find all the code on the web to control it with the raspberry pi
3) add a microphone and a little speaker and use the google Speech API for voice recognition
When you get there, you'll be where most hobbyist can get too easily without needing a lab or expensive equipment. Many people have done very similar projects, just google it, look on YouTube.
The following is multiple choice question (with options) to answer.
if a person remotely controls a machine to do something, which of these is required? | [
"a thing for information",
"these are all incorrect",
"a meal to eat",
"a floral plant life"
] | B | a computer controls a robot |
OpenBookQA | OpenBookQA-304 | mass, velocity, weight
Title: Feathers and Human Flight In the case of Angels where they're supposed to have wings full of feathers and can fly. If we created a flight suit for humans made out of feathers, how big would the feathers have to be?
If the feathers got scaled up would it make it impossible for flight?
If you wanted to flap in order to gain lift, how much weight would be on each arm due to the feathers and how much would you have to flap to gain thrust?
I don't know whether this is the correct forum for this question - it's sort of half biology half physics. To be honest I'm more interested in the maths and physics behind this question. ##Short:##
Given enough assumptions to make the question answerable.
Feather size:
Probably 300 to 500 mm for a small percentage of the feathers
and closer to 50% of that for the majority
Power and force:
Without a complex analysis of flapping flight (with takeoff mode, soaring versus "hovering" capabilities and more) a definitive answer would be difficult, but given the assumptions below, a rough scaling of power with mass seems appropriate, wing loadings (flight mass per area) can be similar and the use of available stronger-than-original non-biological materials should allow an approximately linear scaling of flight-hardware mass with total lifted mass. Power levels required for takeoff appear to be well in excess of those achievable from available human biological sources - something confirmed by all human experience to date.
However, the example of birds such as the Great Albatross and the Wandering Albatross indicate that both power and energy levels required for very long range soaring mode flight should be achievable by human biological power plants. Learning how to do this at all, let alone while sleeping, is yet to be mastered.
Because - read on ...
The following is multiple choice question (with options) to answer.
Thick feathers can be used for | [
"climbing, cracking nuts and peeling fruit skins.",
"courtship and looking for food",
"killing prey, preening and feeding young",
"staying weatherproof, flexible and free of bacteria"
] | D | thick feathers can be used for keeping warm |
OpenBookQA | OpenBookQA-305 | thermodynamics, ideal-gas, adiabatic
When you mentioned a quasi-static process path, I think you were thinking of a stair-step arrangement in which, over each step, the incremental change takes place at constant pressure. This is only an approximation to a perfectly reversible process in which the applied pressure is changing very gradually (with time). However, it is close enough to say that, if you determine the pressure and volume at the beginning and end of each incremental step, to an excellent approximation $P_iV_i^{\gamma}=P_fV_f^{\gamma}$.
The following is multiple choice question (with options) to answer.
Disposition is the process of forming what? | [
"Crystals",
"Rocks",
"Salactites",
"Gemstones"
] | C | stalactites are formed by deposition |
OpenBookQA | OpenBookQA-306 | pressure, fluid-statics, atmospheric-science, buoyancy, gas
Title: Math behind helium balloons lifting objects to (almost) space So I've seen those big helium balloons that are not even filled all the way up, but they still manage to reach heights of up to 30 km. I think they're mainly used for research and etc. Furthermore, I also have noticed that because of the lower pressure higher in the atmosphere helium expands and balloon seems filled up. How do you actually find maximum volume of the balloon according to the height that it has to reach and temperature at that height? And how much helium do you need according to the mass that the balloon has to carry? Take a look at the ideal gas law and Archimedes' principle.
How do you actually find maximum volume of the balloon according to the height that it has to reach and temperature at that height?
The ideal gas law describes how the volume of a gas varies with amount, in mol, of gas particles, pressure, and temperature. You should be able to calculate the volume of helium at high and low altitudes by searching for the pressures and temperatures at those locations. Note that the gas pressure is of the helium in the balloon. This is only slightly larger than the surrounding air (atmospheric) pressure due to any surface tension in the balloon, so we can take the two to be roughly equal.
And how much helium do you need according to the mass that the balloon has to carry?
Archimedes' principle allows you to calculate the upthrust on an object in a fluid (a liquid or gas).
The upthrust is determined by the volume of the object (in this case the volume of the air balloon), and the density of the fluid (here the density of the air at different altitudes).
In order for the balloon to be able to float, the upthrust must be at least as large as the weight of the balloon (the combined mass of the gas and the load).
The following is multiple choice question (with options) to answer.
A balloon is filled with Helium, and then is opened and pressed up to someone's mouth to make a voice high, why does it do this? | [
"gas fills the new area",
"gas easily is dispersed",
"gas moves around freely",
"gas is lighter than air"
] | A | when a gas in an open container evaporates, that gas spreads out into the air |
OpenBookQA | OpenBookQA-307 | ros, gazebo, rviz, urdf, model
<joint name="world_joint" type="fixed">
<parent link="world" />
<child link = "base_link" />
<origin xyz="0.0 0.0 0.1" rpy="0.0 0.0 0.0" />
</joint>
The following is multiple choice question (with options) to answer.
Webbed feet aid in what | [
"penguins laying eggs on ice",
"fish hiding in coral reefs",
"gulls dive bombing fish from the sea",
"ducks chasing prey underwater"
] | D | webbed feet are used for moving faster through water by aquatic animals |
OpenBookQA | OpenBookQA-308 | material-science, physical-chemistry
Title: Melting and Boiling Points of Odd Materials In Chemistry, I was taught that there are three main states of matter: solid, liquid, and gas, and that heat and pressure determine that state. For some substances, the line is blurry between them.
Some materials don't seem intuitively to do this--nor have I been able to find data on them. For example, what is a reasonable estimate of a melting point for brick? What is the boiling point of paper? When will a carpet sublimate?
The common theme seems to be that these are all composite materials. Certainly all the elements have melting points (as applicable) and boiling points. Many compounds do too. However, something like cardboard is a mixture of fiber, glue, pigment, and possibly other things. Each of these might be made up of several compounds, with each compound having its own boiling point.
My suspicion is that for composite materials, individual compounds would exhibit properties roughly individually--so to melt wood, the water would boil off first, and then maybe it would start melting into a glucose-protein slag. Is this truly the right idea for what happens? This is an interesting question, because there is no simple answer - many different things are going on. A quick answer is that many materials don't exhibit clear melting points because heating turns them into something else before they can melt. Here are a couple of examples:
Generally, pure substances have simple, well-defined melting and boiling points. But there are many exceptions. A key example is gypsum - CaSO4 . 2H2O - calcium sulfate dihydrate. When it's heated, it first dehydrates in two steps. Initially it loses 1.5 of the water molecules as vapor, then in a second phase it loses the last 1/2 water molecule as vapor. When this dehydration is complete, the remaining compound is not the compound that we started with - it is now CaSO4. And if heating is continued, much of the CaSO4 will decompose - producing CaO (solid) and SO3 (vapor). Eventually, some melting will be observed, but the melted material will actually be a mixture of CaO and CaSO4.
The following is multiple choice question (with options) to answer.
The melting point of a duck would be | [
"higher than the body temps",
"lower than a refrigerator",
"higher than the sun's",
"lower than a freezer's"
] | A | melting point means temperature at which a solid melts |
OpenBookQA | OpenBookQA-309 | orbital-elements, orbital-migration, orbital-mechanics
Precession doesn't effect eccentricity (which way the Earth is pointed obviously doesn't effect eccentricity), but precession can add to or subtract from Obliquity.
That's the gist of it.
You can run some numbers if you like, but that gets even longer. The sunlight energy that reaches the earth and how it varies by axial tilt is longitude dependent, so any calculations on changes in energy by changes in axial tilt will vary based on longitude. At many latitudes, the summer solar energy is more than double what it is for winter. Even a one or two degree in the angle of axial tilt variation can make a measurable difference in the seasonal variation.
Precession energy variation isn't longitude dependent, but it varies every day with the earth's orbit. Some bad math on it, with the current eccentricity of about 0.0167, what that means is that at perihelion, the Earth is about .9833 AU from the sun and at aphelion, about 1.0167 AU. Because solar energy diminishes with the square of the distance, the roughly 3.4% variation in distance from the sun works out to about 7% more solar energy hitting the Earth perihelion to anhelion. When the Elliptical orbit peaks, that ratio exceeds 20% and when it's minimized, less than 2%, but those are ratios by season and location, the total energy the Earth receives from the sun doesn't change, only seasonal variability changes.
That's as far as I'll go with the numbers, as far as the timing, that's pretty straight forward, some of that covered above:
Axial Tilt, when at a maximum it tends to melt glaciers and leads to warming, this last happened 10,700 years ago and fits with the end of the last ice age. Minimal tilt can lead to cooling and the earth will enter an Axial Tilt Minimum in about 9,800 years. The entire cycle, high to low back to high lasts 41,040 years.
The following is multiple choice question (with options) to answer.
What shows that the Earth being tilted on its axis causes ones side of the Earth to receive less energy from the Sun than the other side? | [
"summer in the USA, winter in Australia",
"snow will be on the North Pole instead of the South Pole",
"seasonal changes take place",
"some countries are warmer than others"
] | A | the Earth being tilted on its axis causes ones side of the Earth to receive less energy from the Sun than the other side |
OpenBookQA | OpenBookQA-310 | zoology, invertebrates, sensory-systems
Regarding the ethics of your "investigation", I'd recommend to just not do it.
Sources:
https://de.wikipedia.org/wiki/Blindschnecke
http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase/home/species?id=1286
https://en.wikipedia.org/wiki/Cecilioides
http://www.molluscs.at/gastropoda/index.html?/gastropoda/morphology/eyes.html
The following is multiple choice question (with options) to answer.
If a creature wishes to hunt, which senses would be avoided? | [
"sight",
"smell",
"crawling",
"hearing"
] | C | smell is used for finding food by some animals |
OpenBookQA | OpenBookQA-311 | infection, amphibians
Title: What is this toad suffering from? Myiasis or chytridiomycosis? I found this toad on Aug. 29th at this location: position on osm
I think it is a bufo bufo, approx. 10 cm long. The nostrils seemed to be completely filled with a grey matter and from the activity of the floor of the mouth it apparently tried to breathe againgst this obstruction. It probably had enough oxygen via its skin though.
I tried to remove the obstruction using a blade of grass but this seemed to produce some pain as the toad closed its eyes on contact, so I stopped. The skin looked fairly normal and the toad was able to walk away after a while.
I can think of two causes for this condition.
Batrachochytrium dendrobatidis infestation
Lucilia bufonivora larvae
I could not see properly, if there were any larvae or unhatched eggs inside the nostrils, but as the rest of the skin seemed unharmed I assume the latter.
Is my assumption valid or is there even a third possibility? It is a female Bufo Bufo and you are right, there are toad fly (Lucilia bufonivora) larvae/eggs inside her nostrills. These flies lay their eggs inside toads' nostrills (specifically on Bufo Bufos) and the larvae start eating them. Sadly this disease ends up by the death of toad. They slowly eat nostrills, then mouth, eyes, and all the head.
Here's a photo of a male bufo bufo, without a head. Someone found it walking around at this situation. https://i.stack.imgur.com/I6twl.jpg
The following is multiple choice question (with options) to answer.
Frogs bury themselves in mud in order to | [
"retain energy",
"bear young",
"find food",
"take a nap"
] | A | An example of hibernation is a frog burying itself in mud |
OpenBookQA | OpenBookQA-312 | asteroids, comets
Title: How significant are the recent results that Scholz’s Star has perturbed several observed hyperbolic objects? The Gizmodo article A Visiting Star Jostled Our Solar System 70,000 Years Ago refers to the the three year old ApJ. paper The Closest Known Flyby of a Star to the Solar System (also arXiv) which describes Scholz’s Star and it's pass close to our solar system about 70,000 years ago.
The Gizmodo article then discusses the newly published paper in MNRAS Where the Solar system meets the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies. However, while I can access the earlier paper, the new result is paywalled and I'm not able to access it (at least not soon).
The second half of the abstract in particular is confusing me.
Here, we perform a systematic numerical exploration of the past orbital evolution of known hyperbolic minor bodies using a full N-body approach and statistical analyses to study their radiants. Our results confirm the theoretical expectations that strong anisotropies are present in the data. We also identify a statistically significant overdensity of high-speed radiants towards the constellation of Gemini that could be due to the closest and most recent known fly-by of a star to the Solar system, that of the so-called Scholz's star. In addition to and besides 1I/2017 U1 (‘Oumuamua), we single out eight candidate interstellar comets based on their radiants’ velocities.
The following is multiple choice question (with options) to answer.
celestial bodies are known to | [
"circle balls of hydrogen",
"travel through deep space",
"crash into each other",
"slingshot around the galaxy"
] | A | planets orbit stars |
OpenBookQA | OpenBookQA-313 | everyday-life
Due to friction effects though, option c is still best. Pedaling hard will quickly deplete energy reserves while pedaling at a slow but steady rate will allow you to cycle for much longer. From a physics point of view, we cannot help you spend less energy, it will inevitable take about the same amount of energy regardless of your method (some +/- due to friction, etc). But by keeping your power usage low, you can go much farther before needing a rest. It is much the same as with running and walking. Simplistic physics says both use the same amount of energy, but you won't get as far by running due to the massive power requirements.
The following is multiple choice question (with options) to answer.
Riding a two wheeled human powered vehicle is good for the environment because | [
"it runs without fuel",
"it helps people stay in shape",
"they are cheaper to maintain",
"they are more fun to drive"
] | A | riding a bike does not cause pollution |
OpenBookQA | OpenBookQA-314 | python, interview-questions, simulation
def breed_animals(self):
babies = []
male_available = False
for animal in self.population:
if animal.gender == 2 and animal.age >= animal.minimum_breeding_age:
#check for at least one male of age
male_available = True
break
for animal in self.population:
if animal.gender == 1 and animal.living:
if animal.pregnant['pregnant'] and (animal.pregnant['months'] >= animal.gestation_period):
animal.pregnant = {'pregnant': False, 'months': 0}
new_animal = Animal(
animal.species,
animal.monthly_food_consumption,
animal.monthly_water_consumption,
animal.life_span_years,
animal.minimum_breeding_age_years,
animal.maximum_breeding_age_years,
animal.gestation_period,
animal.minimum_temperature,
animal.maximum_temperature
)
babies.append(new_animal)
elif (not animal.pregnant['pregnant'] and
animal.minimum_breeding_age <= animal.age < animal.maximum_breeding_age):
fertility = animal.fertility_rate
if (self.food_supply < animal.monthly_food_consumption or
self.water_supply < animal.monthly_water_consumption):
fertility *= .005 # reduces fertility rate if insuff. resources
if dice_roller(fertility):
animal.pregnant['pregnant'] = True
self.population += babies
The following is multiple choice question (with options) to answer.
If an animal is able to reproduce then | [
"that animal has matured",
"that animal was impregnated",
"that animal was in heat",
"that animal was interested"
] | A | reproduction occurs during adulthood |
OpenBookQA | OpenBookQA-315 | As others have said, one can ask that the girls' chairs, and the block of chairs for the boys, be chosen together (in this way, we treat the group of boys as "another girl", for a total of 5 "girls" choosing among 5 "seats"); thus, we can have the boys choose one of the 5 "seats" (in reality, it is their block of chairs), the first girl chooses one of the 4 remaining chairs, the second girl chooses one of the 3 remaining chairs, etc. making for $$5!=5\times 4\times 3\times 2\times 1=120$$ ways of seating the girls and choosing the block of chairs for the boys. Then, all that remains is for the boys to arrange themselves within the block, which there are $$3!=3\times 2\times 1=6$$ ways to do, making (again) a total of $$(5!)\times (3!)=120\times 6=720$$ ways of arranging them.
-
+1 for the graphics! :-) – joriki Jul 8 '12 at 19:53
Thanks!$\text{}$ – Zev Chonoles Jul 8 '12 at 20:00
Treat the group of three boys as an additional girl. That makes five girls, which can be arranged in $5!$ ways. Then you can replace the additional girl by any permutation of the three boys, of which there are $3!$.
-
thanks joriki, but not quiet clear about what you say – user1419170 Jul 8 '12 at 19:49
@user1419170: Could you be more specific? What part isn't clear to you? – joriki Jul 8 '12 at 19:49
this part Treat the group of three boys as an additional girl – user1419170 Jul 8 '12 at 19:51
@user1419170: See Brian's and Saurabh's answers, which use the same idea but phrase it differently. – joriki Jul 8 '12 at 19:53
The following is multiple choice question (with options) to answer.
A kid having a preference is something like | [
"he gets bored easily",
"he likes having dinner",
"he hates eating peas",
"he likes blonde girls"
] | D | preferences are generally learned characteristics |
OpenBookQA | OpenBookQA-316 | food, decomposition
Title: Worm compost cannot have cooked food I live in the Netherlands and it is getting fashionable to compost with worms. After investigating a few websites I noticed that most websites suggested that I cannot feed the worms leftovers from citrus fruits. This seems logical. I then started noticing that people advise against feeding the worms cooked food.
I'm no biologist but I cannot imagine a reason why cooked food is bad for the worms. Could anybody explain why this might be in layman’s terms? There are a few reasons for not feeding cooked foods to worms (Eisenia spp.) in a smaller household size worm farm. It's not because the food is cooked but what it often contains.
The earthworm used in vermiculture is usually Eisenia fetida (red wigglers) though other Eisenia species are sometimes used. All Eisenia are epigeic species meaning they live in the junction of decomposing organic matter (such as leaf litter, aging manure, rotted fallen trees) and their natural food is decaying plant matter and bacteria that are also digesting the organic matter. They don't make use of small dead animals (meat and fat).
In large scale commercial vermiculture operations, leftover and past-due-date foods from restaurants, institutions, nursing homes and schools are used along with plant matter and carboard and paper. I'm not sure how they balance cooked foods but possibly much less is used than plant matter.
The fact food is cooked isn't the problem but what's in it and/or what happens to it when added to the bin. If you have leftover vegetables and fruit that's been cooked with no added salt, it's perfectly acceptable. A certain amount of sweetened cooked fruit is also fine as the worms will eat that too. But ready-made foods usually have preservatives, salt, fats and spices added. Either worms won't eat it, leading to odour caused by mouldy rotten food, or it can make them unthrifty and even killing off your worms if it's fed them repeatedly.
The following is multiple choice question (with options) to answer.
Worms are excellent decomposers because | [
"they eat a lot of rot",
"worms eat dead bodies",
"they enjoy eating carcasses and expel waste back to earth",
"worms enjoy eating dirt and decay"
] | C | decomposition is when a decomposer recycles nutrients from dead organisms to the soil by eating those dead organisms |
OpenBookQA | OpenBookQA-317 | mycology
Does this mean that not only is going to the swimming pool not a cure of fungal infections, but it is actually the cause? Well, maybe not. While the articles show that there is a larger incidence of fungal infections among swimmers, they only show correlation, not causality. People who partake in sports activities have a bigger chance of having these infections than the general public. These are also the people who are more likely to go swimming.
To settle the matter for good, we need an article named "Prevalence of fungal infections among occasionally swimming couch potatoes" :-)
The following is multiple choice question (with options) to answer.
Sickness has the potential to | [
"strengthen an organism",
"test an organism",
"eliminate an organism",
"eat an organism"
] | C | illness has a negative impact on an organism 's health |
OpenBookQA | OpenBookQA-318 | magnetic-fields, earth
Title: Would a compass on its side point at the ground? From a point just north of the equator, A straight line to the Magnetic North would be through the earth. If a compass was turned on it's side, would the north pointing arrow point toward the ground along that straight line? A compass is usually used to find the direction of the horizontal magnetic field of Earth at that point. The needle of a compass is very light and thus its efficiency decreases when the compass is not in the horizontal plane at that point (due to gravity).Therefore, where the compass would point will become unpredictable. But, yes, in ideal conditions, the compass would point along the straight line joining that point to the north pole.
The following is multiple choice question (with options) to answer.
a compass uses iron to locate the northern | [
"latitude",
"axis",
"shoreline",
"hemisphere"
] | B | the floating arrow on a compass always points towards the north |
OpenBookQA | OpenBookQA-319 | reproduction
Title: Why are so many species reproducing late this year? Hope this question is OK for this site, couldn't see where else to ask it.
We've spent a few days out in the countryside recently, and have been very surprised at how many species appear to have very young offspring so late in the season. I was always under the impression that the vast majority of animals and fish produced young in the spring (March/April).
For example, we saw tadpoles, fluffy (ie obviously very young) coots and weeny minnows. I would have expected that all of these would have been born/laid a good 3 or 4 months ago, and so would be more mature by now.
Caveat: We didn't do a scientific study, this is just a strong impression we got from days out in north west England. It's hard to say without more information, but one substantial possibility is that you are mistaken that species are reproducing late - that's a problem with anecdotal rather than scientific data!
Additionally, species you mention like the common coot can attempt multiple broods where the season is long enough. Wikipedia specifically mentions Britain:
Eurasian coots normally only have a single brood each year but in some areas such as Britain they will sometimes attempt a second brood
The same could be true for species of frogs/toads and fish, so without knowing specific species it can't be known whether these are species reproducing again or species reproducing late.
The following is multiple choice question (with options) to answer.
When geese migrate in the late summer or early autumn, they | [
"head to less snowy areas",
"prefer to visit florida",
"take a scenic route",
"travel in small groups"
] | A | migration is when animals move themselves from a cooler climate to a warmer climate for the winter |
OpenBookQA | OpenBookQA-320 | optics, visible-light, vision
Title: How does nearsightedness know what's near versus far? If I wear a VR headset, I still have to wear my glasses, because the image arriving on the surface of my eye is still arriving as if it were actually far away. But how does that work? Why does the image from a distant object arrive at the surface of the eye differently than a near object? Let's start by discussing how the eye works.
As you look around, light rays from objects around you are traveling into your eye. They enter through your pupil, are refracted (i.e. bent) by the cornea and lens in your eye, and finally strike the retina, as shown in this image borrowed from here:
The blue lines represent light rays coming in from a faraway object, the object pointed to by the $P_{small}$ label is the lens, and the surface where the light rays converge on the back of the eye is the retina. The photoreceptors - the cells in the eye that sense light and send it to your brain - are all on the retina, so it's important that the image be fully focused there in order for you to see it sharply.
In this image, we assumed that the object was infinitely far away - in this case, the light rays are parallel to each other. But let's see what happens when we consider objects closer to the eye:
The following is multiple choice question (with options) to answer.
What is the result of an object reflecting light toward the eye? | [
"Being blurred",
"Being Seen",
"Blindness",
"Glare"
] | B | if an object reflects light toward the eye then that object can be seen |
OpenBookQA | OpenBookQA-321 | evolution, zoology
Let's say the environmental challenge for two different kinds of carnivore (let's call them Bogs and Dats) is to catch Mophers. Both Bogs and Dats initially have the same medium-to-short muzzles. Some Bog individuals figure out that they can dig Mophers out of their burrows, and some Dat individuals figure out that they can catch Mophers at night when the Mophers leave their burrows. Both strategies are successful. Some Bogs happen to have longer muzzles than their cousins, and find it turns out that longer muzzles work synergistically with the digging strategy, allowing Bogs to stick their noses into the Mopher burrows to grab escaping Mophers. The resulting fitness advantage results in an increase of the long-muzzle trait in further generations of Bogs. Note that in this scenario it is the adaptive behavioral strategy that creates selective pressure that favors a particular genetic adaptation.
Dats on the other hand, because of their nocturnal hunting strategy, benefit from improved night vision; and long muzzles don't provide any fitness advantage to Dats because Dats don't dig Mophers from their burrows. As long as Bogs and Dats don't hybridize, they will most likely end up with long and short muzzles respectively.
The Waddington effect, also called “Genetic Assimilation”, is somewhat more direct:
An environmental stress causes a proportion of a population to develop one or more abnormal traits, by interfering with embryological development.
If there is a selective pressure in the environment that favors some subset of those traits, individuals whose genetic makeup makes them more likely to develop that subset of traits, those individuals are likely to produce more descendants than other members of the population.
If being “more likely to develop” that subset of traits results from a weakening of genetically determined development controls that would otherwise prevent development of that subset of traits, then the subset of traits can eventually become the normal phenotype.
The following is multiple choice question (with options) to answer.
Two animals with similar diets living in the same environments leads to them | [
"vying for the same prey",
"forming a strong friendship",
"moving to disparate environments",
"adopting different types of diets"
] | A | if two animals eat the same prey then those animals compete for that pey |
OpenBookQA | OpenBookQA-322 | java, swing, minesweeper
}
/**
* Function creates mines at random positions.
* @param s the size of the board(row or column count)
*/
public void createMines(int s){
ArrayList<Integer> list = new ArrayList<>(); //Modifiable array to store pos. of mines.
for(int x = 0; x < s; x++)
{
for(int y = 0; y < s; y++)
{
list.add(x*100+y); // x & y shall be individually retrieved by dividing by 100 and modulo 100 respectively.
// refer to lines 284 and 285 for implementation
}
}
counts = new int[s][s]; //resetting back-end array
The following is multiple choice question (with options) to answer.
What does mining change? | [
"temperatures",
"biological environments",
"water levels",
"atmospheric pressures"
] | B | mining changes an ecosystem |
OpenBookQA | OpenBookQA-323 | thermodynamics, entropy, heat-engine
(Question 1) Where does the energy required for the compression come from?
This is supplied externally. After completing the cycle, the Carnot engine produces net work, but some work is needed to keep it going in some parts of the cycle. This can be done e.g. by using a motor with flywheel. The flywheel temporarily stores excess kinetic energy that can be used to overcome the negative work parts of the cycle.
(Question 2) Why would we divide the compression into two steps? Why can the gas not just be compressed and increase its internal energy so we have more temperature at the (state 1)* to restart all the stuff with more "strength"? What's the point of releasing that internal energy it is gaining from the compression we are forcing?
This question can be answered in several ways, and it depends on personal taste whether you will like mine. First of all, it should be clear that we can't just reverse the previous steps in the process, or there will be no net result. Another crucial element is the fact that compressing some volume takes less work at a lower temperature than at higher temperature. This is why compressors have cooling fins and industrial processes often have intermediate cooling steps (intercoolers). By expanding a hot gas, and compressing it again at a lower temperature, we can realize net positive work.
(Question 3) What's the real beginning of the 2nd law? Where does it come from and how does it apply here, in the engine?
I would recommend looking at the historic developments in the field. As you mention, there are several formulations of the second law. Some are more generally applicable than others, or are more quantitative of nature than qualitative.
The second law is relevant for the Carnot engine, because the thermodynamic cycle is limited to operate between the temperature bounds, because it is impossible to transfer heat from low to high temperature. The formulation of the second law which is most applicable to the heat engine is this: no thermodynamic cycle producing net work can exist which has as only effect the cooling of a single heat reservoir. From this follows that rejecting some heat in a lower temperature heat reservoir is required to produce work. Furthermore, the reversible Carnot cycle is one without entropy generation, from which follows it has maximal efficiency.
Additional clarification
OP had some more questions in comments to the answer.
The following is multiple choice question (with options) to answer.
A car engine is a source of heat and therefore needs | [
"radiator fluid",
"water added",
"wiper fluid",
"gasoline"
] | A | a car engine is a source of heat |
OpenBookQA | OpenBookQA-324 | speed-of-light, measurements, si-units, metrology, length
Title: How is the Length of a Meter Physically Measured? I have two parts to this question.
First, I understand that the meter is defined as the distance light travels in 1/299,792,458 seconds. But how is this distance actually measured? The second is obviously from an atomic clock, but Wikipedia makes it appear that the distance is calculated by the counting of wavelengths. For the count of wavelength to be useful you must calculate the physical length of it, which is dependent on the speed of light, which is defined with meters and to increase the accuracy of the measurement, NIST recommends the use of a specific wavelength of laser (which is in meters). Does this not make the actual measurement of the length of the meter circular? Or does the fact that the speed of light is a constant defined in meter/second over come the appearance of the circular logic? The way I see the circular logic would be if the speed of light ever changed, the length of the meter would also change, which make it impossible for us to know the speed of light changed without referencing it back to an older physical object.
Further, the measurement is done in a vacuum but we can not actually create a perfect vacuum, so I assume there would be a pressure range allowed on the vacuum, and pressure measurements are also based on the definition of a meter (I would think this would further add circular logic to laboratory measurements performed in air and adjusted for refraction).
Second, how is this measurement for the meter actually used to calibrate physical objects? I.e. If I buy a meter stick that has been calibrated against the national standard, how do they actually compare the length of the stick vs the wavelength measurements? The length of a meter bar can be measured using a HeNe laser. The laser used is chosen because we are very good at stabilizing the frequencies it outputs. This means that if we can measure the frequencies before the testing, they will remain steady during the testing. A cesium clock can be used to determine the frequencies of light used with great precision, as the second is defined from said clocks.
Once you have a good measurement of frequency, you have a good measurement of wavelength (assuming a reasonable medium... a vacuum is best, as the speed of light is defined in a vacuum, thus no uncertainty). With a wavelength in hand, you can do interferometry.
The following is multiple choice question (with options) to answer.
A ruler is used for measuring the length of what? | [
"distance between cities",
"air",
"stuff",
"motivation"
] | C | a ruler is used for measuring the length of an object |
OpenBookQA | OpenBookQA-325 | botany, terminology, nomenclature
Regnum Animale: the animals;
Regnum Vegetabile: the plants;
Regnum Lapideum: the minerals (you read it right).
Note that, in this classification, "animals" correspond to what nowadays we call animals and protozoans, and "plants" correspond to what nowadays we call plants, algae, fungi and bacteria.
You have to keep in mind that this book was first published in 1735, well before the evolutionary biology being proposed in the XIX century and established in the XX century. Therefore, it is a book published when fixism was the current paradigm, full of mentions to the scala naturae.
So, the plants (as well as the animals) showed a continuum of species, going to the lower plants (the bacteria) to the higher plants (the flowering ones). It's worth mentioning again that, by that time, bacteria were plants: Phylum Schyzophyta, to be more precise.
Thus, we have "lower plants" and "higher plants", "lower animals" and "higher animals", as well as "lower minerals" and "higher minerals"!
Unfortunately, this terminology is so embedded in the biological sciences that even today, as I mentioned, we struggle to get rid of it.
Just drop "higher plants", whatever it means
As your Wikipedia link says, "higher plants" is a synonym of vascular plants. However, there are a lot of problems here:
First, this is a remnant of the scala naturae and, just because of that, should be avoided. Think of it as a meaningless term, just like "more evolved organism".
Second, there is no clear and indisputable definition of what is a "higher" plant. Some authors used to define the "higher plants" as the Angiosperms only, or the seed plants (Angiosperms + Gymnosperms), or the vascular plants (Angiosperms, Gymnosperms and Pteridophyta).
For instance, in lusophone biology books, it was very common a division in three groups:
lower plants: bacteria and algae;
intermediate plants: bryophytes and pteridophytes;
higher plants: gymnosperms and angiosperms.
The following is multiple choice question (with options) to answer.
Extinction is the term for an organism which..? | [
"Small Population",
"Zero Population",
"Limited population",
"Decreasing Population"
] | B | if a population decreases to zero then that organism is extinct |
OpenBookQA | OpenBookQA-326 | An object with negative charge is brought. In each situation,. AP Physics Practice Test: Impulse, Momentum ©2011, Richard White www. rhythm that continuously repeats a single basic pattern. Repeat steps 1-3 after you tilt the force sensor to an angle with the meter stick. 1c relative to an observer take to pass the observer? The meter stick is parallel to its direction of motion. Physics B and AP Physics C that are appropriate for the AP B level as well as problems from AAPT’s Physics Bowl and U. Calculate the mass of the stick. can someone please help me with this physics problem? A uniform meter stick with a mass of 250 g is supported horizontally by two vertical strings, one at the 0 cm mark and the other at the 90 cm mark (Fig. Below is a picture of the meter stick with labels such as the force and lever arm that cause the torque. The types of kites are as varied as their uses. First, I figured that I had to balance the meter stick on the edge of the table in order to find its center of mass. 8c moves past an observer. hang it on the meter stick. 15 kg meter stick is balanced with a pivot point at the 18 cm mark. Use your Smart Cart as a force sensor by hanging it from. Physics B and AP Physics C that are appropriate for the AP B level as well as problems from AAPT’s Physics Bowl and U. Background. The hooked mass will hang from the string and the binder clip will prevent the string from slipping. Nanometers are a unit most commonly used to measure wavelengths of light. 5) noting that the downward vertical accelerationa of the hanging mass is the same as the horizontal acceleration of the glider. 3 gram rectangle hanging from the right. You will be given the mass and location of a known mass as well as the location of the meter stick support. When two ants meet, they bounce off each other and reverse direction. Physics Lesson 1 to Prepare for UIL Physics Portion of Science Test Lesson Plan Title: Free-Body Diagram Lesson Plan Physics EOC (End of Course) objective 2D - The student demonstrates an understanding of the relationship of force and motion in one and two dimensions. Free online length converter - converts between 93 units of length, including meter [m], kilometer [km], decimeter [dm], centimeter [cm], etc. there's a right and a wrong way
The following is multiple choice question (with options) to answer.
A student is studying different aspects of science, and today's area is magnetic properties. The student has a magnet, and is testing which sort of objects the magnet will have an attraction to. The student is surprised that the magnet tugs itself towards | [
"a plastic cup",
"a plaster wall",
"a grey stone",
"a paper plate"
] | C | rocks sometimes contain iron |
OpenBookQA | OpenBookQA-327 | zoology, behaviour, mammals, rodents
Title: Why do Guinea Pigs chirp / sing? Ok, so this appears to be quite a mystery. Me and my girlfriend have 2 Guinea Pigs, 1 male and 1 female.
My girlfriend once picked up the female one and took her outside into our garden. The Guinea got scared for some unknown reason and jumped out of my girlfriend's arms and fell down hard.. That night, the female Guinea woke us up with some very strange sounds. She sounded like a chirping bird.
Since then, she sometimes repeats these sounds (most often at night, but not always). Mostly, we are puzzled as to why as there is often no apparent reason for her sounds. Also, when she makes the sounds, she appears to be in a trance-like state, making no movements at all.
Looking for the answer online I found many discussions on the subject like this one or this one. Mostly, the sounds (and the often mentioned trance like behavior) appear to be interpreted as either (1) alarm sounds, (2) loneliness sounds or (3) happiness sounds.
There are also recordings of it one Youtube, like this one.
What I was wondering:
Does anybody know about some actual research that has been committed on this subject? If so, what were the results?
I'm just so very curious to find out! I found this question very interesting so I did some research. Here's a brief summary of what I've found:
Researchers have found that there are 11 different call types. Some of these include a "sharp alarm cry", "sociable clucking", chutter, whining, purring etc. Using body position and behaviour, researchers attempted to associate these vocalizations with behaviour. Some vocalizations had no apparent associated action including what researchers designated the "chirrup" ( I think this is similar to what your guinea pig might have emitted.)
For more information you can read the results section of this paper by Berryman. You can find a full description of each of the 11 calls and their assumed cause or purpose. Some involve social interaction, reproduction, and distress. Much of the research regarding Guinea pig vocalization involves communication and response between mothers and pups.
In short, it seems as though this chirping behaviour your Guinea pig is exhibiting is normal, but not of any known cause.
The following is multiple choice question (with options) to answer.
Which is most likely to cause an animal to shiver? | [
"5 degrees celsius",
"42 degrees Fahrenheit",
"6 degrees Celsius",
"8 degrees Celsius"
] | A | cold temperatures cause animals to shiver |
OpenBookQA | OpenBookQA-328 | paleontology, fossils, desert
Title: Why are many fossils found in deserts? Why are deserts famous for fossils? Is it a coincidence? Some examples:
Giant Catfish Fossil Found in Egyptian Desert
Chile's stunning fossil whale graveyard explained
Giant Dinosaur Fossil Found in Sahara Desert I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago. The fact that a location today is a desert has no indication of what the climate, or even where on the globe that location was 50 or 100 million years ago.
Do not forget about plate tectonics and climate change. One can go to places like the Judith Basin in Montana, a relatively harsh area of North American Bad Lands, desert or near desert like conditions with cold winters and find fields of fossils from animals that are believed to have lived in tropic marshes of in oceans, because at the time those animals lived, what is now Montana was not inland, and was not at a Northern location. Millions of years ago it was an undersea plate, thus it has layers of limestone made from ancient single cell sea creatures and sometimes larger objects that were entrapped and preserved as larger fossils. At other times, those plates rose from the sea floor and homed some of the large creatures, like T-Rex that lived, thrived and sometimes survive as fossils.
Later, that plate move and ended up inland, in what is not North America. Glaciers, wind, and water may have stripped off many layers of deposits and left exposed or close to exposed the layers of interest to fossil hunters. Desert regions tend to be subjected to this type of erosion and exposure making such finds easier. If those same fossils were in and area such as a rich planes area with plentiful plant growth and never subjected to glacial scouring, they could be, and may very well be, right below your feet but under many layers of soil and decaying vegetation, river sediment and other deposits rendering them out of sight and out of reach.
The following is multiple choice question (with options) to answer.
While many habitats support a great variety of life, and deserts are included, many animals | [
"freeze in deserts",
"starve in deserts",
"are abandoned there",
"drown in deserts"
] | B | a desert environment contains very little food |
OpenBookQA | OpenBookQA-329 | optics, visible-light, everyday-life, diffraction
Addendum 2: Before the comments below were cleaned out, there was some discussion there about the usefulness of this phenomenon as a quick self-diagnostic test for myopia (nearsightedness).
While I Am Not An Opthalmologist, it does appear that, if you experience this effect with your naked eye, while trying to keep the background in focus, then you may have some degree of myopia or some other visual defect, and may want to get an eye exam.
(Of course, even if you don't, getting one every few years or so isn't a bad idea, anyway. Mild myopia, up to the point where it becomes severe enough to substantially interfere with your daily life, can be surprisingly hard to self-diagnose otherwise, since it typically appears slowly and, with nothing to compare your vision to, you just get used to distant objects looking a bit blurry. After all, to some extent that's true for everyone; only the distance varies.)
In fact, with my mild (about −1 dpt) myopia, I can personally confirm that, without my glasses, I can easily see both the bending effect and the sharpening of background features when I move my finger in front of my eye. I can even see a hint of astigmatism (which I know I have; my glasses have some cylindrical correction to fix it) in the fact that, in some orientations, I can see the background features bending not just away from my finger, but also slightly sideways. With my glasses on, these effects almost but not quite disappear, suggesting that my current prescription may be just a little bit off.
The following is multiple choice question (with options) to answer.
Moving your face further from a mirror | [
"will make your face appear bigger",
"will make your face appear in macro",
"will make your wrinkles less obvious",
"will make it easier to see your pores"
] | C | if an object is close then that object will appear large |
OpenBookQA | OpenBookQA-330 | tissue
Title: Tissues in plants and animals
What is the equivalent connective tissue in plants?
Connective tissue in animals are mostly made up of collagen.
What about in plants?
Connective tissue in animals are mostly made up of collagen
Tissue is not like a simple chemical mixture ; rather tissue means a group or assemblage of cells, obeying certain defining-characteristics.
Animal connective tissues contain collagen mostly in the extracellular matrix. There are also other cell-constituents like phospholipid(membranes), DNA, RNA, etc. Blood is a liquid connective tissue which do not contain collagen in its matrix (plasma)
What is the equivalent connective tissue in plants?
Connective tissue is defined as all the tissues originated from the mesoderm layer of the animal embryo.
Now plants have a different mode of development than animals (plausibly due to evolution in separate route). So no part of a plant-body is homologous with a part of animal-body. It is impossible to bring a compare.
However; plants too; have their extracellular matrix; which is more popular as plant's cell wall (that contain cellulose, hemicellulose, etc.) as well there are intercellular spaces.
Still, if you forcefully want to bring a comparison; then the ground-tissue system of plant maybe called as a rough analogy with connective tissues in animals ( Similarly epidermal tissue of plant maybe a rough analogy with epithelial tissue of animals)
The following is multiple choice question (with options) to answer.
Special tissues in plants transport minerals throughout the plant such as | [
"water",
"starch",
"spices",
"sugar"
] | D | special tissues in plants transport minerals throughout the plant |
OpenBookQA | OpenBookQA-331 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
The wolf raises his family near a | [
"den",
"field",
"tree",
"mother."
] | A | animals live and feed near their habitats |
OpenBookQA | OpenBookQA-332 | thermodynamics, climate-science
Title: Where does all the heat go during winter? I do not understand where actually the heat in our surroundings go during the winter season. Is it radiated out into space? I know it cannot coz global warming would not be a issue then. It might get absorbed but where? I tried figuring it myself but couldn't please help.
Where does all the heat go during winter?
There is less energy coming from the sun in the form of electromagnetic radiation impinging on the land during winter.
Depending on the latitude, in regions where there is winter , the difference is large.
The closer to the equator the smaller the effect of "winter".
So it is not where the energy goes, but why it does not fall , and this is explained to first order by the inclination and the distance to the sun during the orbit of the earth.
In general , a body in space radiates energy away the rate depending on various conditions, like green house gases, cloud cover, convection , albedo ...the numbers change . It is the continuous radiation from the sun that keeps replenishing the energy so that the earth does not freeze. During winter at high lattitutes , less energy comes and cold settles.
The following is multiple choice question (with options) to answer.
something could get wedged during winter if which of these happens? | [
"trapped water changes physical form repeatedly",
"water flows down a stream",
"water drank by a person",
"none of these"
] | A | cycles of freezing and thawing water cause ice wedging |
OpenBookQA | OpenBookQA-333 | the-sun, light, rotation, planetary-atmosphere
Title: Why is twilight longer in summer than winter and shortest at the equinox I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with that all year.
While doing some research for this, I noticed something that surprised me. Check out this disparity between astronomical sunrise to civil sunrise for the solstices and equinox (the latter two adjusted for daylight saving time):
Date/Astronomical/Civil/Disparity
Dec 20: 0533 - 0640 (67 minutes)
Mar 20: 0526 - 0630 (64 minutes)
Jun 20: 0320 - 0451 (91 minutes)
To be honest, these sets of ranges surprise me for multiple reasons. I clearly don't know what I don't know, but here are some questions I can formulate:
Why would twilight be longer in summer than winter? Before seeing this data, I had assumed that since the sun makes a more perpendicular path through the horizon in summer that twilight would be shorter in summer than in winter. After all, in winter the sun takes a "slanted" path across the horizon. Wouldn't the summer's path be more direct and therefore quicker?
OK: seeing this empirical evidence I conclude that something is wrong with my premise that forms my first question. Summer twilight is longer in summer than winter. However, I still would have assumed that March 20 would have had a twilight length in between the two solstices. But it's not! Why does the equinox have the shortest twilight?
Appended 5/13/2014:
I didn't want to leave my original incorrect statement in here without flagging it. As Cheekhu points out below, the sun does not follow a more perpendicular path in summer than winter, as I had erroneously assumed and stated above. See his post for more details. See this diagram,
The following is multiple choice question (with options) to answer.
What is an example of the sun being directly overhead at noon? | [
"shadows disappear at noon",
"the shadows on trees are longest at noon",
"sundials can tell time easiest using shadows",
"the sun is hottest at noon"
] | A | the sun is located directly overhead at noon |
OpenBookQA | OpenBookQA-334 | gravity, water, space, planets
The only detail left is how to get a surface temperature that's in the right range for the surface to be liquid. This depends on the distance from the star, but also on the composition of the atmosphere. On Earth, the atmosphere's composition is mostly due to the action of the biosphere, which keeps the temperature regulated in just the right range for water to be liquid. Perhaps it's possible to imagine life on such a water world, in the form of photosynthesising algae-like organisms, which might play a similar role.
The following is multiple choice question (with options) to answer.
What does gravity cause substances on a planet? | [
"things to move sideways",
"things to be moved upwards",
"things to descend to the lowest surface possible",
"things to stay in the same place"
] | C | gravity causes substances to be pulled down on a planet |
OpenBookQA | OpenBookQA-335 | release energy by transferring heat to their surroundings. In older works, power is sometimes called activity. the bungee cord has more potential energy when it is stretched out than when it is slack. , green plants convert solar energy to chemical energy (commonly of oxygen) by the process of photosynthesis. Practice questions A bowling ball is lifted to a height […]. kinetic energy = mass * velocity² / 2 E = m * v² / 2. The maximum energy stored in the inductor is LI2/2 with I = I MAX. Efficiency can be explained as the amount of work done by an object to the total energy spent. You can think of a trebuchet as a see saw! Yes, a see saw is really all that a trebuchet is. Example of Few questions where you can use this Mechanical Energy Formula calculate the Mechanical energy of the object have mass 10 kg and velocity 3m/s and height above the ground is 10 m calculate the Kinetic Energy,Potential energy and Mechanical energy of the object have mass 1 kg and velocity 2m/s and height above the ground is 50 m. Kinetic energy = Joules Kinetic Energy Calculator is a free online tool that displays the kinetic energy of the object. Contribute to Ghostlydestinypolice/Physics_Energy development by creating an account on GitHub. We cover most electrical devices and home appliances, our online calculators can be edited to fit any home appliance and accurately calculate power costs. 2 Kinetic Energy. Current (I) is measured in amps (A), using an ammeter. The units of power are watts, the units of energy are joules. The kinetic energy just before impact is equal to its gravitational potential energy at the height from which it was dropped: K. 94u2rotkh0qgw ts2269o179 taplsbcnrzp02 tqj6cos4hnt038 862fohcw5vw 0kib5khqvn7x7u imx0rwjjl87j 7v6n0lvam9qps6 1ep3ku4gpb4 7jfyw1bfipc qndzw85umfgmg 3hdpzbzs6my yeu4magtr0k3kw0 e9wp756pxxgsa
The following is multiple choice question (with options) to answer.
The running of the bulls in mexico is a source of what type of energy for the object? | [
"running of bulls",
"solar power",
"animals",
"kinetic"
] | D | motion is a source of kinetic energy in an object |
OpenBookQA | OpenBookQA-336 | photons, vision
Title: Dark room lights When I lay down in my room at night it's pretty much completely dark but I observe this strange phenomenon going on.
When I lay down and look at my ceiling I can see my white fluorescent white bulbs and white fan blades but when it's dark I can't. But, as soon as I avert my eyes from the fan and lightbulbs about 1 foot I can see them in the dark but why? If it helps there is a very slight illumination from the street lights. And, also I can't see anything not white on the ceiling.
Why can I see the objects only when I avert my eyes? This is really a biology topic, rather than a physics one.
The light sensing cells in your eyes come in two (or four depending on how you count) types. The cones are color sensitive. The rods are sensitive over almost the whole visible spectrum and offer no color discrimination, but they are considerably more sensitive than the cones.
The rods and cones are not evenly distributed in the eye. Cones are concentrated in the central part of the retina and rods are more common in your peripheral visual region. Which makes your peripheral vision more sensitive to very dim sources than your central vision.
In fact, naked-eye star-gazers learn to look near-but-not-at very dim observing target exactly to take advantage of this effect. But it take a lot of will-power to do at first. You'll find your self having a "Ah-ha!" reaction and then looking right at the target every time you make the trick work. At which point you have to go around again.
The following is multiple choice question (with options) to answer.
a lighter object hue can lead to what? | [
"none of these",
"positive charge in electricity",
"a bad electric conduction",
"ability to see yourself in it better"
] | D | as lightness in color of an object increases , the ability of that object to reflect light will increase |
OpenBookQA | OpenBookQA-337 | solar-eclipse
Title: Viewing 2017 Solar Eclipse - How important is it to be in the center(blue line)? I'm viewing the 2017 Solar Eclipse in Graham County, NC. How important is it to be in the center(blue line)?
It is almost entirely national forest there so it would be fairly easy to get to assuming I can park somewhere.
http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2017_GoogleMapFull.html If you want to see a total solar eclipse, you just need to be between the two red lines on that map. As long as you're within there, what we call the "path of totality", you will be able to see a total solar eclipse.
If you are outside of the red lines, you will only see a partial solar eclipse. This map shows what percentage of the sun will be covered the further north or south you are of the line.
Graham County is entirely within the path of totality, so you should see a total solar eclipse. If you're planning to travel, however, it might be too late. Most campgrounds and hotels within the path are already full. If you're already within the path of totality, my recommendation would be to stay put. Travelling on that day, or even that week, will be difficult.
The center of the path of totality will offer the longest viewing for the eclipse. The further from the center, the shorter it will last. The aforementioned map shows timings at different distances from the center. Notice that it also helps to be close longitudinally as well as latitudinally (that may not be a word).
The following is multiple choice question (with options) to answer.
When looking at an eclipse, an important thing to remember is | [
"to take a photograph",
"to look through a window",
"to use hands to shield eyes",
"avert eyes at all costs"
] | D | looking directly at an eclipse of the Sun causes harm to the eyes |
OpenBookQA | OpenBookQA-338 | volcanology, volcanic-hazard, volcanic-eruption
Title: Would a Yellowstone eruption destroy global agriculture? Someone recently claimed in my hearing that if the Yellowstone caldera were to erupt, the resulting ash cloud would end all agriculture for a year or two. (The speaker is not a scientist, and neither am I.)
Is that accurate?
Are there reasonable scenarios (i.e., not this) worked out for the effects of a supervolcano eruption?
I did see this question, where one of the commenters points out that such an event would be unprecedented, so our ability to predict is limited, but I'm still curious about whatever we do know at this stage. An eruption of the Yellowstone super volcano would cause agricultural disaster over a very large area. Its global effect would be significant, but not totally devastating.
The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.
But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.
Eruption of super volcanoes is rare which makes it difficult to ascertain what exactly would happen when the Yellowstone super volcano eventually erupts - which won't be any time soon.
Yellowstone last erupted 174 000 years ago, which was a minor eruption. Lava from Yellowstone won't be the problem, but the ash and gases will be.
The last major eruption, 630 000 years ago, covered much of western and central United States with ash. The maximum thickness of the ash from that eruption is 660 ft. The eruption was a double eruption, 170 years apart. The amount of ash thrown into the atmosphere with each eruption caused the ocean to cool by 3 degrees Celsius with each eruption.
The following is multiple choice question (with options) to answer.
A small volcano under the sea erupts ever four years. After a few centuries, there will be | [
"new ground to inhabit",
"a large fish eating a tree",
"a burst of fire from the future",
"a small crack in a tall mountain"
] | A | an island is formed by lava cooling on the ocean floor over time |
OpenBookQA | OpenBookQA-339 | greedy-algorithms, packing
Title: Does a greedy strategy exist for this instance of the Bin Packing Problem? I was wondering whether I can solve the following problem by using a greedy strategy: Let's say that I have a set of containers with 2 dimensions (width and height) and a set of items also with 2 dimensions. Can a solution be found where each item is assigned to a container so that it fits inside? I can have containers left over; however, all of the items must be assigned. Assuming a solution exist, is there a greedy choice I can make for assigning an item to a container? No, a greedy approach would not guarantee a solution for this problem (regardless of whether this solution is optimal or not). To see why, proceed by reduction. Suppose that you could actually find a solution for your problem in polynomial time using a greedy approach. Then, you could use your algorithm to solve in polynomial time the decision version of the Bin packing problem, which is known to be NP-complete (and, therefore, unlikely to be solvable in polynomial time).
How does this reduction work?
The decision version of the Bin packing problem involves deciding whether a certain number of bins (for example, 9) is optimal. If your hypothetical polynomial-time greedy algorithm finded a solution for 9 bins and failed to find a solution for 8 bins, then the answer for the decision problem would definitely be yes, and no otherwise.
Greedy is actually good.
All that being said, to obtain an approximate solution, a greedy approach is, probably, the best heuristic: sort the items in decreasing order of size and insert them one by one into the first bin that has room for it. This heuristic is called first-fit decreasing. The main appeal of this heuristic is that we pack the big items first and hope that the little ones fill up the spaces.
The following is multiple choice question (with options) to answer.
Putting a cardboard box in a bin instead of the trash can | [
"conserve energy for later",
"save wild animal species",
"keep it from the trash",
"reduce the height of landfills"
] | D | recycling resources has a positive impact on the environment |
OpenBookQA | OpenBookQA-340 | arachnology
Title: Did or do these gigantic spiders really exist in Finland and/or Northern Europe? In the year 2000, the newspapers in a small coastal town of Finland ("Hanko"; current population: ~8k) had some very disturbing reports of a couple who had just moved into a new rental apartment/house in the central part of the town, and there encountered these monstrous spiders that look like they come straight out of a horror movie. In fact, apparently, they are literally the kind of spiders used in the classic spider horror movie "Arachnophobia"...
Digging through old things recently, I encountered the saved newspaper pages and was shocked by just how large and disgusting they look. I must have repressed this whole thing for the last 21 years, since I first heard about it when it was current. From the oddly-worded Swedish-language report (clearly not written by somebody with perfect Swedish skills), it's not made clear whether the couple was "just" working on fixing the place up, or if they actually had already moved in and saw these monsters while they were there to sleep. But the basic point is that the spiders allegedly existed at all, and may well still exist...
The article also notes that these spiders were "common" in Denmark in the beginning of the 1900s, further creeping me out. My initial assumption and hope was that these spiders had miraculously survived in their undisturbed habitat for 50 years (the article also mentions that they were "last spotted" in the 1950s), and that they were not native to Europe at all, but simply had been accidentally shipped in a crate with exotic fruits or something from some tropical island somewhere back in the day, and had not spread but simply hung around in their little basement in a place which, somehow, just happened to not have any humans going there for all these years.
The article further mentions that some kind of professor had determined them to be Tegenari Atrica spiders. However, looking them up on Wikipedia, I got redirected to the disturbingly named article "giant house spider", where it's mentioned that these are:
among the largest spiders of Central and Northern Europe.
And:
original habitat consists mostly of caves, or dry forests where it is found under rocks, but it is a common spider in people's homes.
The following is multiple choice question (with options) to answer.
Spiders catch their prey with | [
"a silky thread",
"trickery",
"seduction",
"a flyswatter"
] | A | a spider web is used to capture food by spiders |
OpenBookQA | OpenBookQA-341 | atmosphere, ocean, hydrology, climate-change
Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.
Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.
Waves come about from wind, so they're a twice-indirect form of solar power.
Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.
How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of about 1400 Watts per square metre. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.
So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$
The following is multiple choice question (with options) to answer.
Which has renewable resources? | [
"natural gas formations",
"oil well",
"plastic bag",
"Pacific Ocean"
] | D | water is a renewable resource |
OpenBookQA | OpenBookQA-342 | thermodynamics
Title: Real world heat transfer? I would appreciate it if someone can advise me if my idea of heat transfer is correct. I would like to transport frozen products and below is my idea of insulating them.
From what Ive found online there are 3 modes of heat transfer: conduction, convection and radiation.
To limit heat transfer by conduction, my plan is to place my products inside a corrugated cardboard box lined with 0.75inch EPS expanded polystyrene foam sheets on all sides. My guess is that conduction on the bottom would contribute the most heat because my products are packaged in a way that the bottom is flat (and in constant contact with the bottom foam) and the top is mostly air, so I would probably increase the base to 1.5inch EPS foam.
To limit heat transfer by convection, I would use a cardboard box that has as little empty space inside the box as possible when filled. I was also planning to place 1/4in flat ice packs but Im not sure whether to place it on the top or bottom of the box. If I were to place it on the top of the box would there be an 'air current'(convection) since cold air is more dense? If I were to place it on the bottom of the box would the top part of my product melt?
As for radiation I wouldn't worry too much because at the most an aluminum foil layer would suffice since it reflect 95%? of heat by radiation and foil is light.
Obviously I don't have enough real world data so general speculation would suffice. I live in a tropical country, usually around 34C in the afternoon. Let's also assume 2 scenarios, one where the box is exposed to the sun and 1 where it isn't.
PS shipping company doesn't allow dry ice.
Basically I would like to know if:
The following is multiple choice question (with options) to answer.
Which of these would let the most heat travel through? | [
"a cotton candy at the store",
"the new pair of jeans",
"the steel spoon in the cafeteria",
"a calvin klein cotton hat"
] | C | metal is a thermal conductor |
OpenBookQA | OpenBookQA-343 | metals
Title: Why does carbon alloy with iron specifically? Everyone knows what an alloy is: it's a metal made by melting two (or more) other metals together.
Unless of course you're talking about steel. That's a metal made by mixing carbon (very much not a metal) into molten iron. But you never hear about carbon alloys with any other metal, and that's kind of strange. If a few percentage points of carbon can turn iron into the miracle metal that is the foundation of the Industrial Age, just imagine what it could do to aluminum or titanium, for example. (Or even bronze, for that matter, which is superior to iron in many ways, from a materials science perspective.)
But you only ever hear about carbon alloying with iron to form steel. So what's so special about iron? It's true they are not common, but there are other alloys that use carbon. Nickel is probably one of the more common metals that form alloys with carbon that have desirable properties. For example, Nickel 200, Nickel 201, and Nickel 205 all contain carbon. (See: http://www.asminternational.org/documents/10192/1852239/ACFA9D7.pdf/d490dee6-620e-4e38-b64d-53dd02c5fc81). Chromium and Tungsten also form alloys with carbon called Stellite Alloys: See http://en.wikipedia.org/wiki/Stellite (although some, but not all, stellite alloys contain iron too).
The following is multiple choice question (with options) to answer.
The material that makes up iron nails is known as what on the table of elements? | [
"Nail.",
"Fe",
"Copper",
"Au"
] | B | iron nails are made of iron |
OpenBookQA | OpenBookQA-344 | geology, mineralogy, minerals, weathering
To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.
My suggestion to use the term weathering or weathered.
The following is multiple choice question (with options) to answer.
An example of weathering is | [
"a smooth sandy beach",
"a smooth river stone",
"a tall pine tree",
"a large sharp boulder"
] | B | weathering means breaking down surface materials from larger whole into smaller pieces by weather |
OpenBookQA | OpenBookQA-345 | electrical-engineering, telecommunication, wireless-communication, communication
So in order to pick up a tag that is directly under it we need our RFID reading satellite to broadcast with around 63,000 TW of power, about 2.5 times the total worlds power output.
To locate a tag you'd need a range of several times this (add an extra 0 or two to the power number), you can't fly directly over every point on the earth, and a fleet of satellites to give reasonable coverage. But those are relatively small issues in comparison to getting it to work with a single satellite to start with.
These numbers may be off by a little bit. In fact they could well be off by a lot. But unless I've gotten it wrong by a factor of a few million it's not even close to being practical.
The following is multiple choice question (with options) to answer.
Some people put metal tags on their dog's collars, because in darkness, these collars can | [
"melt wax",
"reflect light",
"read books",
"stain clothes"
] | B | shiny things reflect light |
OpenBookQA | OpenBookQA-346 | hydrology, mountains, rivers
Title: Why do rivers have 'wells' in mountains? Why/how can rivers have sources in places high above the sea level? The presence of water underground has nothing to do with sea level in mountainous country.
When rain fails on a mountain, or snow falls on a mountain and the snow eventually melts, the water from the rain or snow melt mostly travels downhill via rivers to the sea.
In getting to a river some of the water will fall on the ground. In places where the ground is covered by soil, water can travel through the soil via the pore spaces between the grains of soil. Similarly if porous rock, such as sandstone lies beneath the soil water can travel through the pores in the rock.
If a layer of impervious rock lies under the porous rock or soil, the water cannot move downwards, due to gravity, any further. This can lead to water accumulating in the soil or porous rock and saturating the soil or rock. In such situations an aquifer can form. The top of the saturated zone in an aquifer is called a water table.
The ground beneath a river is saturated and the surface of the river shows the water table exposed to atmosphere. Thus in mountainous regions the ground beneath rivers will be saturated and capable of supporting a well developed from the bank of a river.
The following is multiple choice question (with options) to answer.
What can explain that a body of water is a source of water? | [
"a bird sitting in a bird bath",
"a child splashing in a tub",
"a person drinking from a glass of water",
"a deer drinking from a lake"
] | D | a body of water is a source of water |
OpenBookQA | OpenBookQA-347 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
Inanimate things may be pollinators such as | [
"bees",
"birds",
"wind",
"deer"
] | C | pollination is when wind carry pollen from one flower to another flower |
OpenBookQA | OpenBookQA-348 | the-sun, light, distances
Title: At what distance wouldn't the Sun cast a visible shadow anymore? How far from the Sun would a (dwarf) planet have to be so that the Sun is dim enough that it doesn't cast a shadow when you're standing on the planet? What magnitude is the border in brightness beyond which a shadow isn't visible anymore? This depends on eye biology, so there's no purely astronomical answer. I'll note that Venus is just about capable of casting a shadow (at greatest elongation, with ideal conditions) so let's say that a magnitude -5 object is at about the biological limit of casting a shadow.
The sun has a magnitude -27, so that is 22 magnitudes brighter than Venus. 5 magnitudes is a factor of 100 in brightness, so 20 magnitudes is a factor of 100000000 (100 million) and 22 magnitudes is about 600 million.
But light follows an inverse square law, The square root of 600 million is about 25000. So at about 25000 times the distance of Earth, or 0.4 light-years, the sun would be as dim as Venus at its brightest and perhaps marginally able to cast a shadow for someone with acute vision, on a good matt white surface. This puts our astronaut in the Oort cloud.
There's a good deal of uncertainty in this estimate, based on eye acuity. So let's say "something between 0.1 and 1 light-years"
The following is multiple choice question (with options) to answer.
A person's shadow is smallest at what time? | [
"4:00 pm",
"8:00 am",
"12:30 pm",
"6:30 pm"
] | C | as a source of light moves directly overhead of an object , the size of the shadow of that object will decrease |
OpenBookQA | OpenBookQA-349 | energy, energy-conservation, antimatter, higgs, dark-energy
Title: Can we in the far future have an energy source made from vacuum energy, antimatter, dark energy, Higgs boson? Can we in the far future have an energy source made from vacuum energy, antimatter, dark energy, Higgs boson and all kind of these like stuffs?
@userLTK Higgs boson is a particle that give mass to other particles
,so why can't it be used for an energy source hypothetically
The following is multiple choice question (with options) to answer.
The source of a type of energy we use is a | [
"planet",
"star",
"meteor",
"rock"
] | B | the sun is the source of solar energy called sunlight |
OpenBookQA | OpenBookQA-350 | equipment, history-of-chemistry
Title: Help me identify this glassware! I'm a freshly graduated physics and math teacher moved into a small school from the late 1920s. The equipment here is old and confusing, at the very least. I have found many things which I have never seen before. I would like some help identifying what I have and what I can do with them, if anything.
(Click the images to view them at full size.)
1. A load of copper pots. For boiling something perhaps?
2. Some sort of wash bottle? Why is the cork on there?
3. I managed to make out "unitized wash bottle" on the back. This serves the same function as the last one, I presume.
4. It reminds me of a graduated cylinder until the frosted top and the "arms" that poke out the sides. What is this for?
5. This reminds me of halogen bulbs. Again, I have no idea what this is for.
6. I've taken to calling this "trumpet" glass pipe. What is it used for?
7. This large bulb has confused me since day one. I feel like it needs some sort of current passed through the ends. It reminds me of a cathode ray tube in a way. I'm completely lost on this one.
8. Here. Have a free safety poster! Not as good as old Carol, though. #4 is a collection vessel of some sort.
The ground glass fitting would have connected to some other ground glass fitting. A set of the ears would be on the connecting piece of glassware also. Then springs would hold the two pieces together.
The following is multiple choice question (with options) to answer.
if a great water traveler took inventory of their tools, which of these would be in it? | [
"a big cooking spoon",
"a north facing item",
"a big chopping board",
"a big iron bender"
] | B | a compass is used to navigate oceans |
OpenBookQA | OpenBookQA-351 | evolution, botany, proteins
tl;dr: the egg contains more proteins than the seed because the chicken that made the egg ate a whole lot of seeds, and all the protein in those seeds ended up concentrated in that one egg.
EDIT: running into this much later I realized I missed a pretty vital half of the question, because there is a difference between fruits and seeds. The difference is the following: nitrogen is precious for plants so they'll try and use it for very important things. Seeds are very important to the plant, so while a seed has less protein than an egg it will still have lots of protein by plant standards. Fruits now, that's another story. Like the sugary nectar, fruits are a bribe for animals, a bit of food offered to them so that they'll spread the plant's seeds. And like with the sugary nectar, the plant has every incentive to pack that bribe full of cheap carbohydrates and as few precious proteins as it can manage.
The following is multiple choice question (with options) to answer.
What contains seeds | [
"human.",
"whole pumpkin",
"soda can",
"leaf"
] | B | a pumpkin contains seeds |
OpenBookQA | OpenBookQA-352 | organic-chemistry, catalysis, green-chemistry
Title: How does the work that won the 2012 Sustainable Chemistry Award contribute to sustainable chemistry? I'm seeking a lay explanation for how the work of Dr Marc Taillefer that won the 2012 European Sustainable Chemistry Award, contributes to sustainable chemistry.
From the press release, Dr. Taillefer
is being recognised for his seminal contribution to the field of
homogeneously catalysed coupling reactions leading to C—C, C—N, C—O, C—P bonds. His team at
the Institut Charles Gerhardt, ICG (Montpellier, France) is investigating for a decade the
environmentally sustainable conversion of small molecules into more valuable substances
catalysed by copper and iron molecular complexes. This renaissance of “Ullmann type arylations” is now often used at the academic or industrial level and avoids the use of more expensive catalysts based on palladium.
The objectives of the award are (to quote from this press release) to:
Recognise individuals or small research groups which make an outstanding contribution to sustainable development by applying green and sustainable chemistry.
Promote innovation in chemistry and chemicals that will deliver clear improvements in the sustainable production and use of chemicals and chemical products.
Demonstrate that chemistry and chemicals can play a central role in delivering society’s needs, while minimizing and solving environmental problems. His work is about developping new catalysts based on copper and iron, to replace to traditional catalysts based on palladium. Copper and iron are both very common elements in nature, while palladium is considered a high supply risk (see the 2012 British Geological Survey risk list for details).
The new RSC Visual Elements Periodic Table can be used to check this kind of information.
The following is multiple choice question (with options) to answer.
To have a positive impact on the environment | [
"leave lights on",
"take shorter showers",
"use Styrofoam plates",
"take longer showers"
] | B | conserving resources has a positive impact on the environment |
OpenBookQA | OpenBookQA-353 | friction
as expected.
So the blocks will slide over one another if
$\dfrac {F_1M + F_2m}{M+m} > Fr_{max} = \mu mg$
If $F_2 > F_1$ then a similar calculation gives the same condition.
The following is multiple choice question (with options) to answer.
If one mineral can scratch another mineral then that other mineral is softer than that one mineral, as can be tested with | [
"a diamond and steel",
"a rock and glass",
"a diamond and agate",
"a ruby and salt"
] | C | if one mineral can scratch another mineral then that other mineral is softer than that one mineral |
OpenBookQA | OpenBookQA-354 | earth, the-sun
Title: Latest sunrise/earliest sunset out of phase with solstice? Everybody knows that the shortest and longest days of the year occur on the solstices. However, examination of sunrise/sunset tables shows that the maxima and minima of sunrise/sunset times are offset from the solstices by about 10 days.
According to timeanddate.com for my location (Portland, OR), for the winter solstice, the earliest sunset is about December 10 (16:27), and the latest sunrise is around January 1 (07:51).
This is counterintuitive... what's the explanation? The point here is that sunrise and sunset does not only move towards or away from noon, but noon itself moves around 12:00. There is a difference between "civil time" (the one counted by wall clocks) and "solar time" (the one marked by sun clocks). This difference is called the "Equation of Time" and its geometrical shape is called the Analema.
So in order to have the earliest sunset you need a combination of both a short day and a noon moved before 12:00. Same reasoning for latest sunrise.
You can see more about the Equation of Time on Wikipedia: http://en.wikipedia.org/wiki/Equation_of_time
The following is multiple choice question (with options) to answer.
John, who lives in Minnesota, noticed that the time between sunrise and sunset was the shortest it had been for an entire year. The month was most likely to be | [
"July",
"January",
"September",
"April"
] | B | the amount of daylight is least in the winter |
OpenBookQA | OpenBookQA-355 | ### Show Tags
05 Nov 2009, 00:50
29
1
16
Let's go step by step:
First operation: 3L-1L=2=6/3L of wine left, total 4L;
#2: 6/3L-(6/3)/4=6/3-6/12=18/12=6/4L of wine left, total 5L;
#3: 6/4L-(6/4)/5=6/4-6/20=24/20=6/5L, total 6L;
#4: 6/5L-(6/5)/6=6/5-6/30=30/30=6/6L, total 7L;
....
At this point it's already possible to see the pattern: x=6/(n+2)
n=19 --> x=6/(19+2)=6/21=2/7L
_________________
##### General Discussion
SVP
Joined: 29 Aug 2007
Posts: 1712
Re: A container has 3L of pure wine. 1L from the container is taken out an [#permalink]
### Show Tags
04 Nov 2009, 10:32
1
virtualanimosity wrote:
Q: A container has 3L of pure wine. 1L from the container is taken out and 2L water is added.The process is repeated several times. After 19 such operations, qty of wine in mixture is
1. 2/7 L
2. 3/7 L
3. 6/19L
Thats a too tough to calculated.
Got (2/7)L in A - After a lengthy calculation.
Intern
Joined: 25 Oct 2009
Posts: 16
Schools: Wharton, HBS, Stanford
Re: A container has 3L of pure wine. 1L from the container is taken out an [#permalink]
### Show Tags
04 Nov 2009, 15:18
1
1
Initial q-ty: 3L
1 operation: +2L-1L=+1L
19 operations: +19L
The final q-ty of mixture (or denominator) is 3L+19L=22L. How it can be transformed to X/7 or X/19? What have I missed?
The following is multiple choice question (with options) to answer.
if a person gets some fruit wine for a gift, how can they measure its volume? | [
"they can use a cylinder with unit markings",
"none of these",
"they can use a tape measure",
"they can use a thermometer"
] | A | a graduated cylinder is a kind of instrument for measuring volume of liquids or objects |
OpenBookQA | OpenBookQA-356 | thermodynamics, photoelectric-effect, thermal-conductivity, absorption, solar-cells
Title: Possibility of combining photovoltaics and solar thermal energy In a private setting, photovoltaics and solar thermal energy are often harvested on the home's roof and roof area is limited. So, I thought about combining both, i.e. mounting solar collectors underneath solar cells. The rationale behind this is that the solar cells appear almost black and probably heat up considerably under irradiation. So if the collectors are in tight thermal contact to the cells, the water in the collectors might carry away the heat as usable energy, and possibly even increase the lifetime or efficiency of the cells due to the cooling effect (but this is rather engineering and not part of the question). So roof area is exploited twice (in two different wavelength windows). Moreover, if electric energy from the cells exceeds actual consumption and the battery's storage capacity, it might also be used for heating (albeit at a lower total efficiency, of course).
Can the amount of (infrared) radiation that gets absorbed (or possibly transmitted) by solar cells, and which is available as heat at the back side of the cells, be quantified by a rough calculation and either prove or disprove the benefit of such a concept? Does the almost black appearance of the solar cells fool one into thinking that they also absorb in the infrared, although they don't? Temperature of PV panels increases significantly during the day and their conversion efficiency decreases with increasing temperature. I had access to measurements of a PV plant and it showed that the total power production was about the same in August (middle of summer) and October (early fall). Although the days were shorter and there was less solar irradiance in October vs August, the air temperature was significantly lower making PV panels more efficient. For the outside temperature of 35 C, the PV panels can easily reach 70 C!
The following is multiple choice question (with options) to answer.
Absorbing sun rays | [
"raises the Fahrenheit of an object",
"lowers the Celsius of an object",
"causes the object to cool",
"causes the temperature of the object to descend"
] | A | if a substance absorbs solar energy then that substance will increase in temperature |
OpenBookQA | OpenBookQA-357 | energy, sun, stars
Then figure that cooking meat with sunlight does require at least some sort of magnifier, so we can probably multiply that by a factor of at least 3, and probably more like 7-10 or so.
Of course, for now I'm ignoring a such minor details as how you even design (not to mention building) a system even close to that size. There would be decidedly non-trivial challenges involved. For example, the largest mirrors we've built yet have diameters around 10 meters (or non-round mirrors of roughly equivalent area). These are already built in sections, with a computer to control movement of the individual pieces to maintain the illusion of a single mirror acting as a unit. Trying to multiply that out to multiple kilometers--well, I don't think anybody's even contemplated what that would take yet.
The following is multiple choice question (with options) to answer.
What did some ancient societies use to reflect light? | [
"wood",
"plants",
"clothing",
"rocks"
] | D | a mirror is used for reflecting light |
OpenBookQA | OpenBookQA-358 | organic-chemistry, catalysis, green-chemistry
Title: How does the work that won the 2012 Sustainable Chemistry Award contribute to sustainable chemistry? I'm seeking a lay explanation for how the work of Dr Marc Taillefer that won the 2012 European Sustainable Chemistry Award, contributes to sustainable chemistry.
From the press release, Dr. Taillefer
is being recognised for his seminal contribution to the field of
homogeneously catalysed coupling reactions leading to C—C, C—N, C—O, C—P bonds. His team at
the Institut Charles Gerhardt, ICG (Montpellier, France) is investigating for a decade the
environmentally sustainable conversion of small molecules into more valuable substances
catalysed by copper and iron molecular complexes. This renaissance of “Ullmann type arylations” is now often used at the academic or industrial level and avoids the use of more expensive catalysts based on palladium.
The objectives of the award are (to quote from this press release) to:
Recognise individuals or small research groups which make an outstanding contribution to sustainable development by applying green and sustainable chemistry.
Promote innovation in chemistry and chemicals that will deliver clear improvements in the sustainable production and use of chemicals and chemical products.
Demonstrate that chemistry and chemicals can play a central role in delivering society’s needs, while minimizing and solving environmental problems. His work is about developping new catalysts based on copper and iron, to replace to traditional catalysts based on palladium. Copper and iron are both very common elements in nature, while palladium is considered a high supply risk (see the 2012 British Geological Survey risk list for details).
The new RSC Visual Elements Periodic Table can be used to check this kind of information.
The following is multiple choice question (with options) to answer.
To positively impact the environment | [
"toss plastic bottles in trash receptacles",
"use plastic knives and forks for every meal",
"scrap metal from old buildings is processed to be used for new construction",
"buy a less fuel efficient car"
] | C | recycling nonrenewable resources has a positive impact on the conservation of those resources |
OpenBookQA | OpenBookQA-359 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
A skill some humans have is | [
"ten fingers",
"vision",
"heart beating",
"talking"
] | D | skills are learned characteristics |
OpenBookQA | OpenBookQA-360 | thermodynamics, electricity, electrons
Title: Why does Joule heating not occur when no current flows through a conductor? Joule heating happens every time when the conduction electrons transfer kinetic energy to the conductor's atoms through collisions, causing these conductor's atoms to increase their kinetic and vibrational energy which manifests as heat. Then, why wouldn't it happen when no current is flowing through the conductor? When there is no current, the electrons are still moving randomly at a speed of $\mathrm{~10^5\ m/s}$, but at a zero average velocity.
Then, why don't these electrons collide with the atomic ions making up the system and transfer energy to them causing them to heat up even when no net current is flowing? When no current is flowing, the system is in thermal equilibrium. The electrons do transfer kinetic energy to the atoms through collisions, but the atoms also transfer kinetic energy to the electrons, and these two processes happen at the same rate, so there's no net energy transfer and the system neither heats up nor cools down. This is just the same as any other case of thermal equilibrium: effectively, the electrons and the atoms are at the same temperature, and that's why there's no heat flow.
However, when you switch the voltage on there is an electric current accelerating the electrons, which increases their kinetic energy. Now they have, on average, more kinetic energy to give to the atoms than the atoms have to give to them. This means that there is a net transfer of energy from the electrons to the atoms. Moving an electron in an electric field changes its potential energy, and this is where the energy for the heating ultimately comes from.
The following is multiple choice question (with options) to answer.
A switch is used to stop the flow of currents which causes Joule heating in | [
"thermostat",
"solar energy",
"magnetic fields",
"electrical circuit."
] | D | a switch is used to stop the flow of current in an electrical circuit |
OpenBookQA | OpenBookQA-361 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
Birds eat nuts, but sometimes they eat | [
"wolves",
"bugs",
"dogs",
"cats"
] | B | birds sometimes eat insects |
OpenBookQA | OpenBookQA-362 | meteorology, atmosphere, wind, air-currents
Title: Where does wind come from? Wind is (according to Wikipedia) the flow of gases on a large scale.On the surface of the Earth, wind consists of the bulk movement of air.
What forces would cause such a mass movement of air? Wind is caused by pressure differences. Think of a balloon full of air; poke a hole in it and the air comes out. Why? Because the pressure in the balloon is higher than outside, and so to regain equal pressure, mass moves and that is the wind.
There is a bit more to this in the atmosphere as the Earth rotates and near the surface friction also plays a role. The equation of motion is the Navier-Stokes and in vector form in Cartesian space is:
$$\dfrac{\partial\mathbf u}{\partial t} = - \mathbf u \cdot \nabla \mathbf u -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g + \mathbf F$$
In this equation, $\mathbf u$ is the vector wind, $(\mathbf u \cdot \nabla)$ is the advection operator, $\rho$ is density, $\mathbf \Omega$ is the vector rotation of the Earth, $\mathbf g$ is effective gravity and $\mathbf F$ is friction.
The LHS is the time rate of change of the wind at a point in space (as opposed to following the parcel). The RHS represent a number of factors that produce a change in the wind. From left to right:
Advection of momentum (non-linear)
Pressure gradient force (this is wind blowing from high to low pressure)
Coriolis force (this turns wind to the right in the NH and left in the SH and causes the wind to flow parallel to isobars)
gravity (provides hydrostatic balance with the PGF in the vertical)
Friction (in the boundary layer you may see this as $\nu\nabla^2\mathbf u$)
The following is multiple choice question (with options) to answer.
air masses are pushed by westerlies but stopped by | [
"gravity",
"meandering air currents",
"currents",
"sunlight"
] | B | jet streams may deflect the air masses moved by the prevailing westerlies |
OpenBookQA | OpenBookQA-363 | fluid-dynamics, conservation-laws, continuum-mechanics
So -- when you can, pick conservation form because then you only need to numerically-hack your problem for a few terms instead of all of them. The fewer places you can add non-physical things, the better the end result will be!
The following is multiple choice question (with options) to answer.
An example of conservation is avoiding | [
"oil",
"sunlight",
"fats",
"tea"
] | A | An example of conservation is not using fossil fuel |
OpenBookQA | OpenBookQA-364 | physiology, homework
Title: Order of events in hibernation
Arrange this in sequence :
i. Heat loss exceeds heat production.
ii.As body temperature falls, heat loss decreases.
iii.Body temperature equals environmental temperature.
iv.Metabolic activities fall to the basal level.
I am confused between i,iii,ii,iv and iv,i,ii,iii. I think the order i,ii,iii should be correct, since the fall in temperature occurs after the heat loss exceeds production and will continue only till the temperature equals the ambient temperature. iv is the reason for i. Hence iv,i,ii,iii sounds pretty convincing to me.
With i,iii,ii,iv , the main problem is that there can not be any appreciable fall in temperature ii after the temperature equals the environmental temperature iii. And iv seems more probably to be the reason for i rather than the reverse
The following is multiple choice question (with options) to answer.
After a long winter's hibernation, a female bear and her two cubs exit their cave and begin to search for food. One place they check is | [
"dry sticks",
"dirt pile",
"berry bushes",
"dead leaves"
] | C | bears eat berries |
OpenBookQA | OpenBookQA-365 | programming, qiskit
Which will output:
┌───┐
q_0: ┤ X ├
└───┘
┌───┐┌─────┐┌───┐
q_0: ┤ H ├┤ qc1 ├┤ Z ├
└───┘└─────┘└───┘
New circuit with controlled:
q_0: ───■───
┌──┴──┐
q_1: ┤ qc2 ├
└─────┘
Decomposed new circuit:
┌────────┐ »
q_0: ┤ P(π/2) ├──■───────────────────■───────────────────────────■──»
├────────┤┌─┴─┐┌─────────────┐┌─┴─┐┌──────────┐┌─────────┐┌─┴─┐»
q_1: ┤ P(π/2) ├┤ X ├┤ U(0,0,-π/2) ├┤ X ├┤ U(0,0,0) ├┤ RY(π/4) ├┤ X ├»
└────────┘└───┘└─────────────┘└───┘└──────────┘└─────────┘└───┘»
« ┌──────┐ »
«q_0: ──────────────■──┤ P(0) ├──■────────────────■────────────────■──»
« ┌──────────┐┌─┴─┐├──────┤┌─┴─┐┌──────────┐┌─┴─┐┌──────────┐┌─┴─┐»
«q_1: ┤ RY(-π/4) ├┤ X ├┤ P(0) ├┤ X ├┤ U(0,0,0) ├┤ X ├┤ U(0,0,0) ├┤ X ├»
« └──────────┘└───┘└──────┘└───┘└──────────┘└───┘└──────────┘└───┘»
« ┌────────┐
«q_0: ┤ P(π/2) ├──■───────────────────■──────────────
« ├────────┤┌─┴─┐┌─────────────┐┌─┴─┐┌──────────┐
«q_1: ┤ P(π/2) ├┤ X ├┤ U(0,0,-π/2) ├┤ X ├┤ U(0,0,0) ├
« └────────┘└───┘└─────────────┘└───┘└──────────┘
The following is multiple choice question (with options) to answer.
Which is a complete circuit? | [
"a refrigerator that is running",
"a battery removed from a toy",
"a clock that is wound-up",
"a fuse that has blown"
] | A | a complete electrical circuit is a source of electrical energy |
OpenBookQA | OpenBookQA-366 | newtonian-mechanics, classical-mechanics, biophysics
Title: Walking & Swinging How can I show that the most convenient way to move the arms while walking is swinging them back and forth, alternatively?
To pose the question in another way: can I prove, starting from the conservation of momentum and angular momentum, that given a rigid solid body moving at constant speed and with two appendices on the side, this appendices will move as our arms do when we walk "freely"? This is a responce to usumdelphini's comment:
Is there a way to show this formally, without relying on experimental data?
I'm not going to attempt a deep analysis of walking, but it's fairly straightforward to show that using your arm reduces twisting. Suppose you're looking down on the person walking from above, and suppose they're a cylinder $^1$. Then you'd see something like:
When you move your right leg forward this takes some force $F$, and by Newton's third law there is an equal and opposite force on the point where the leg is attached to your body (the green dot). This causes a torque on your body of:
$$ T = Fr $$
and as a result your body will tend to twist clockwise.
Now suppose you move your left arm forward at the same time:
Moving your arm creates a torque of $T_{arm} = fr$ in the same way, but the torque is in the opposite direction. So the net torque on your body is:
$$ T = Fr - fr = (F - f)r $$
and the result is that your body will twist less.
$^1$ traditionally we assume everything is spherical, but I'll make an exception in this case
The following is multiple choice question (with options) to answer.
Pressing your appendages against an object can allow one to | [
"sense differences in atomic structure",
"sense differences in color",
"sense differences in atomic value",
"sense differences in material makeup"
] | D | touch can be used for detecting texture |
OpenBookQA | OpenBookQA-367 | diffusion
Title: Permeability of containers to poop smells I do a lot of hiking trips that involve driving for an hour or two to the trailhead in the predawn hours. I'm a morning pooper, so I need to poop during the drive. Before COVID, I would usually plan a stop along the way at a Starbucks, get coffee, and use their bathroom. Then if necessary I'd also use a bathroom at the trailhead. Right now, during COVID, these bathrooms are all closed, so my new normal is that I pull over somewhere in the countryside, poop, collect my poop using one of my dog's poop bags, and bring it with me to a town or trailhead where I can dispose of it.
Sometimes this was stinking up my car, even though the bag was tied shut, so I tried putting the poop bag inside a large plastic (PETE) can that some nuts came in, and sealing it with the screw-on lid. Even then, there have been times when the smell seeped out within 30 minutes. Sometimes the smell has been like sour milk, sometimes like sulfur or eggs.
If I want to make this work better, what should I be focusing on? Is ~0.5 mm of PETE likely to be permeable to the smelly volatile compounds involved? Or is the issue more likely to be that there's a poor seal at the screw threads? Would I be better off trying something like the glass jars with clamping lids that people use for their coffee? A tupperware-style container with an o-ring seal? What kind of material should I be looking for in a gasket or o-ring?
(The other option I've tried successfully is to clamp the poop bag under a windshield wiper, so it's outside. But I'm worried this would, uh, catastrophically fail if I then drove at freeway speeds.) The problem likely is not (so much) the plastic material of your container, either solid, or bag.*) Assuming there is no contamination on the outer side of the container, most likely the smells are noticed because of closing the container by either knot or lid is not tight enough.
The following is multiple choice question (with options) to answer.
if a student needs to travel with their lunch for long distances, which of these would have the freshest meal? | [
"a student with freshly cooked food",
"a student with food containing preservatives",
"raw uncooked fish meal",
"a student with uncooked beef"
] | B | as ability to preserve food increases , the ability to transport food increases |
OpenBookQA | OpenBookQA-368 | thermodynamics, laser, cooling
For conductive heat transfer, a useful characteristic time is $\frac{L^2}{D}$, where $L$ is a characteristic length over which conduction is occurring and $D$ is the material thermal diffusivity. Within one or several of these characteristic times, conduction has nearly eliminated the initial temperature difference. The Fourier number, a very well-known nondimensional parameter in heat transfer analysis, captures this relationship.
Note that this $\frac{L^2}{D}$ characteristic time is obtained by a scaling analysis; it captures general trends but is not exact. As another example, for a heating pulse spreading out in a 1-D domain, Crank's Mathematics of Diffusion gives a solution of
$$T(x,t)-T_\infty\sim t^{-1/2}\exp\left(-\frac{x^2}{4Dt}\right);$$
where we find a coefficient of $\frac{x^2}{4D}$ in the exponential term but also a $t^{-1/2}$ factor in front.
Other $t_\mathrm{char}$ parameters can be defined for different heat transfer mechanisms, such as radiation. It's a matter of solving the heat equation subject to the initial and boundary conditions and locating the exponential or exponential-like terms or sum of terms.
The following is multiple choice question (with options) to answer.
Thermal conduction occurs when | [
"I leave a log poker in the fire",
"I sit down on a bed",
"I wave a flag in the air",
"I have a party"
] | A | when a cooler object touches a warmer object , thermal conduction occurs |
OpenBookQA | OpenBookQA-369 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
Plants brought to the western United States from the eastern United States often die because of | [
"bad planting methods",
"small spaces",
"the wrong climate",
"people kill them"
] | C | a plant requires a specific climate to grow and survive |
OpenBookQA | OpenBookQA-370 | plate-tectonics, mountains, tectonics
Title: What is the impact of divergent tectonic plates on old mountain ranges? I found this question, which is similar to what I'm wondering, but my question is slightly different:
What happens if a new divergent boundary forms in a way that bisects a mountain range, especially one formed by converging plates -- and is that even possible?
Purely for the sake of example, if a divergent rift somehow formed on the North American plate, dividing the Appalachians [ETA: apparently I circled a valley, please pretend I'm not a geography-illiterate dork and that it's actually some old mountains.]:
What would happen to the circled area? Anything? Would the mountain range be recognizable after an ocean formed between them? Considering the timescale involved, perhaps an older range would be unrecognizably eroded? I've tried to find examples in the real world, but my Google-fu fails me.
Somewhere I picked up the idea that the Appalachian and Welsh coal seams were once connected or formed together (I think it may have been from an offhand comment in a movie about Welsh miners, so a] maybe I understood wrong and b] who knows how accurate it was), so I initially wondered if that might be an example of what I'm curious about. Unfortunately, some light research seems to indicate that's not the case (if I'm understanding this and this correctly, the connection ends at "both formed, at least partially, during the Carboniferous.)
I'm most interested in what the effects (if any) would be on older mountain ranges such as the Urals or Appalachians, but if anyone knows what kind of effects it might have on younger, taller ranges, I'd love to hear about it.
If anyone has sources I could look into for a deeper understanding, I'd love to have those as well! My lack of knowledge is distressing me to no end. The example of the East African Rift was given in a different answer.
Splitting of mountain ranges in two becomes even more apparent as you go up north from there.
The Red Sea between Egypt and Saudi Arabia is a young new spreading ocean, that cuts through Precambrian mountains.
The following is multiple choice question (with options) to answer.
A tiny spark grows and the result tears through an area of nature and spreads through the mountains, consuming | [
"bark and canopies",
"a crystal lake",
"a snowy mountaintop",
"a small bird"
] | A | wildfire is when a forest catches fire |
OpenBookQA | OpenBookQA-371 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
Near which location would an anteater most likely live? | [
"swamp",
"anthill",
"river",
"bee hive"
] | B | most predators live near the same environment as their prey |
OpenBookQA | OpenBookQA-372 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
One of Kangaroo's unusual features are | [
"They have horns",
"They speak English",
"They can fly",
"webbed feet"
] | D | webbed feet are used for moving faster through water by aquatic animals |
OpenBookQA | OpenBookQA-373 | the-sun, orbit, planet, earth
Is the spiraling movement caused by sun movement (on its path shown
above) where the sun is dragging the earth (and other planets)?
No, the Sun's and the Earth's mutual gravity cause the Earth to rotate around the Sun. The Milky Way's gravity causes our Solar System to revolve around the galactic center. The Sun and the Earth are on the same plane and moving through the galaxy together. The Earth would still rotate around the center of the Milky Way if the Sun magically disappeared.
Does the earth go in front of the sun then back, then fourth and back
like it is shown on the video? I see both the sun and earth racing
with each overtaking the other over and over. Is this assumption true?
In this manner, would earth, at one point in time, be closer to the
destination where the solar system is heading (I think they call the
destination Vega) than the sun?
If you consider a plane tangent to the Sun's velocity vector, then the Earth will pass across that plane twice per year, appearing "in front of" and then "behind" the Sun. This is simply a geometric result since the Earth and Sun share another plane. I wouldn't call any future position of the Solar System a "destination" without evidence the Solar System was sentient, but I am not a philosopher.
I am working on a poetry piece. If I mention that earth and sun are
locked in a never ending race with each taking the lead (earth moving
in front of the sun's path / winning) and earth actually dropping out
of the race (spiraling/moving out the race and falling behind), that
they are destined to never meet (collide), would I be correct?
We haven't ruled out the possibility that the Sun may someday envelope the Earth: What will "the Earth being consumed by the Sun" look like?. Also, the Earth isn't likely to leave its orbit before that time, but the Solar System is chaotic on long time scales. However, your poem would be consistent with current models, and we (humans) don't conclusively know how the Solar System will end. So my two cents is that your poem doesn't contradict modern astronomy. Besides, what's the use of a poetic license if you don't use it?
The following is multiple choice question (with options) to answer.
As the earth orbits the sun | [
"various places experience different weather patterns",
"weather is consistent world-wide",
"weather is always different",
"we all have snow"
] | A | Earth orbiting the Sun causes seasons to change |
OpenBookQA | OpenBookQA-374 | neuroscience, brain, pain
Let's take stabbing as another cause of pain. One stab in a less dangerous place missing all important structures may be not that harmful but may be painful. However multiple small stabs into important structures like arteries or spinal cord could be horribly destructive.
Then let's look at headaches or nerve pain. Here it is only the pain and usually there isn't any destructive or harmful process. Most individuals would take one really, really bad headache followed by never having a headache then chronic daily "tension" headaches.
Psychologically though usually the chronic daily pain is the worst. Particularly as without adequate pain management from the start, it is less responsive to painkillers (analgesia). It frequently adds to depression if it does not cause it itself and can lead to suicide. Also painkillers themselves may cause chronic pain which does not help.
In summary, acute severe pain suggests something is seriously wrong and needs to be dealt with immediately biologically as there is likely a damaging process underlying it. However if this event is survived, it may be linked with high disability from any biological process that underpinned the pain. Chronic daily pain suggests a long continuing process. The cause of this may be life threatening, such as cancers, but is usually less dangerous at least compared to acute severe pain biologically. However the psychological aspects of this pain are seriously important as they can be particularly detrimental.
The following is multiple choice question (with options) to answer.
When a person gets hurt physically, the person feels pain because there are | [
"magic receptors",
"electric reactions",
"making nervous",
"loud nerves"
] | B | nervous system is an electric conductor |
OpenBookQA | OpenBookQA-375 | species-identification, zoology, ornithology
Title: Identification by tail feather I saw the remains of a bird today I did not recognize, and it was pretty mangled so it was hard to describe it. It was about the size of a robin. However, it had a dark brown mottled body like nothing I have ever seen. I have included below a tail feather from the bird which is 5 inches long. I am sure it is not a thrush or a woodcock or a kestrel. So what was it?
Location is Great Bay, Portsmouth, New Hampshire, United States. I believe this is a tail feather (or retrix) from an adult male eastern whip-poor-will (Antrostomus vociferus). See right image below (click to zoom):
.
Source: USFWS Forensics Laboratory
Details:
The brown, mottled appearance and the size (~12 cm) match that of the OP's specimen.
A great resource for exploring bird feathers: https://www.fws.gov/lab/featheratlas/
The whip-poor-will's breeding grounds include the OP's location (i.e., New Hampshire), and according to All About Birds this species could still be present even late in the year ("they seem to leave between early September and late November.").
Orange is breeding. Source: All About Birds.
The whip-poor-will is a medium sized bird and similar in size to an American robin.
Whip-poor-will: 22-26 cm ; Robin: 20-28 cm
Eastern whip-poor-will, (c) Paul Cools, source: inaturalist
The following is multiple choice question (with options) to answer.
During a sandstorm, a bird looks for a | [
"worm",
"mate",
"stream",
"bush"
] | D | shelter can protect animals from weather |
OpenBookQA | OpenBookQA-376 | java, json, rest, spring
@RequestMapping(value = "/cars", method = RequestMethod.GET)
public ResponseEntity<List<Map<String, Object>>> listAllCars() {
try {
List<Map<String, Object>> result = muscleCarService.listAllCars();
return ResponseEntity.status(HttpStatus.OK).body(result);
} catch (Exception e) {
return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
}
}
@RequestMapping(value = "/update-car/{id}", method = RequestMethod.PUT)
public ResponseEntity<Void> updateCar(@PathVariable("id") int id, @RequestBody MuscleCar muscleCar) {
try {
muscleCarService.updateCarFromList(id, muscleCar);
return ResponseEntity.status(HttpStatus.OK).build();
} catch(Exception e ) {
e.printStackTrace();
return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
}
}
}
Service
@Service
public class MuscleCarService {
@Autowired
private MuscleCarDao muscleCarDao;
public MuscleCar getCar(int id) {
if (id <= 0) {
throw new IllegalArgumentException("ID can not be 0 or <0");
}
return muscleCarDao.getCarFromList(id);
}
public void removeCarFromList(int id) {
if (id <= 0) {
throw new IllegalArgumentException("ID can not be 0 or <0 or this id do not exist");
}
muscleCarDao.removeCarFromList(id);
}
public List<Map<String, Object>> listAllCars() {
List<Map<String, Object>> result = muscleCarDao.listAllCars();
if (result.size() > 0) {
return result;
} else {
return null;
}
}
The following is multiple choice question (with options) to answer.
Roads need repaved in spring because | [
"they are cold",
"road need it",
"they are lumpy",
"ice ruins them"
] | D | cycles of freezing and thawing water cause ice wedging |
OpenBookQA | OpenBookQA-377 | visible-light, sun, weather
Title: Why are clouds lighter than the sky during the day but darker at night This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during sunset but apparently it's common in bigger cities).
Basically what I'm wondering is why clouds during the day appear lighter than the sky (white vs light blue) while clouds at night and during the evening appear darker than the sky (see image).
Image quality is low because I took it with my phone through my window.
I guess the clouds could be blocking the light and therefore appear darker but in that case, shouldn't the same thing be happening during the day? There could be quite a few things going on.
Off the bat there's no incoming light for them to scatter: during the day, clouds are white because the water droplets are big enough for all visible light to cause Mie scattering, but if you don't have much light falling on them, you can't observe the scattering and you can't observe light passing through either.
Then you could consider the fact that in some places, it rains more in the evening/night than during the day (if you have hotter surface temperatures during the afternoon, you see cloud formation and precipitation during the late evening, and with the lower temperatures in the night, the air is more likely to become saturated, see Dew Point), and clouds which precede rain are thicker and denser. They don't allow much light pass through.
And lastly, there's less ambient light which they can reflect back towards you.
The following is multiple choice question (with options) to answer.
On a rainy day the clouds are | [
"low",
"small",
"white",
"gray"
] | D | clouds produce rain |
OpenBookQA | OpenBookQA-378 | the-moon, earth, light, satellite
Title: Why does the Moon appear gray when passing between the Sun and the Earth? Shouldn't the Moon appear as bright as a full Moon seen at midnight from Earth?
The photo was taken by DSCOVR at Lagrange point 1.
In the picture, The Moon appears dark gray. Of course the Earth appears bright, reflecting sunlight from clouds and water. The Moon's surface is gray and should reflect less light than the Earth.
It should be irrelevant that we see the far side, since the reflectivity of the Moon's surface should be the same on the far side as the side that faces the Earth.
The midnight full Moon appears much, much brighter as seen from Earth than it does in this picture, despite the fact that the amount of sunlight reflecting from the surface of the Moon is the same in both instances.
I understand the photo was taken with 3 separate exposures of red, blue and green, but this should not affect the brightness.
So why does it appear so dull? That's what it really would look like if you were there with DSCOVR. The albedo of the Moon is only about 0.136, about half of the Earth's average albedo. Of course the part with clouds is higher.
I was shocked too, but it was explained in written copy that accompanied the release of the original image.
Shouldn't the Moon appear as bright as a full Moon seen at midnight from Earth?
It does. If the moon were a diffuse, white ball, a full moon would be about seven times brighter!
If you watch the image or GIF, the Moon is roughly the same brightness as central Australia or the Sahara region.
Phil Plait explains well in Bad Astronomy.
There's a lot to read here.
EDIT: I just ran across these images of astronauts on the surface while reading this answer. Their suits are not 100% white to begin with, but the Lunar soil - at least in these locations - is significantly darker. It is close to the same color as the (presumably) nearly-black radiator fins for the heat sink of the RTG unit (2nd photo) at the astronaut's foot.
above: "Buzz Aldrin carries the EASEP." from here
above: "Astronaut Alan L. Bean from Apollo 12, put the Plutonium 238Pu Fuel from the Lunar Module into the SNAP 27 RTG" from here.
The following is multiple choice question (with options) to answer.
The moon's surface | [
"has asteroid impact marks",
"is smooth all over",
"is filled with lakes",
"has a stronger gravitational pull than Earth"
] | A | the lunar surface contains many craters |
OpenBookQA | OpenBookQA-379 | stereochemistry, carbohydrates
If you want to make models, at your next wine and cheese party get some toothpicks, and two pieces each of four different kinds of cheese. Put four of the cheese chunks on the end of the toothpicks, and then stick the tooth picks in a sausage or something. Then make an exact copy. After that is done, exchange two of the cheese chunks on one model and investigate what you have. There should be no way you can twist or turn or rotate one model to have its kinds of cheeses in the same orientation as the other. Once you have done this, the following picture will make much more sense:
The following is multiple choice question (with options) to answer.
I use a knife to chip away at what to make a sculpture | [
"A slab of rock",
"A bucket of sand",
"A glass of water",
"A bag of air"
] | A | scraping an object may cause small particles to break off of that object |
OpenBookQA | OpenBookQA-380 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
An animal living in an environment lacking in food resources | [
"will be in poor shape",
"will be thriving and lively",
"will be switching to a new diet",
"will hibernate until more food comes along"
] | A | an animal requires enough nutrients to maintain good health |
OpenBookQA | OpenBookQA-381 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
If plants are going to grow, their seeds need to | [
"travel elsewhere",
"be eaten",
"pass a test",
"be washed"
] | A | plant requires seed dispersal for reproduction |
OpenBookQA | OpenBookQA-382 | geothermal-heat, open-data, mining, canada
Title: Canadian equivalent to AMLIS database? I am interested in in situ coal fires. In furtherance of this, I am hoping to find a database of Canadian mine reclamation sites, complete with incident or status reports and descriptions of specific problems.
I've poked around a very small bit in the Federal Contaminated Sites Inventory, but I'm hoping there might be something a bit more specific or targeted out there -- something more like the equivalent of the United States' Abandoned Mine Load Inventory System (AMLIS) database.
Any pointers? Try:
Federal Contaminated Sites Inventory
as well as
Crown Contaminated Sites Database (British Columbia)
Orphaned/Abandoned Mine Site Rehabilitation (Manitoba)
Abandoned Mines Information System-AMIS (Ontario)
The following is multiple choice question (with options) to answer.
A coal mine is what? | [
"a person who mines for coal",
"a rare type of stone",
"a place where coal is processed",
"a mine that is beneath the earth where coal is found"
] | D | coal mine is a source of coal under the ground |
OpenBookQA | OpenBookQA-383 | everyday-life
Due to friction effects though, option c is still best. Pedaling hard will quickly deplete energy reserves while pedaling at a slow but steady rate will allow you to cycle for much longer. From a physics point of view, we cannot help you spend less energy, it will inevitable take about the same amount of energy regardless of your method (some +/- due to friction, etc). But by keeping your power usage low, you can go much farther before needing a rest. It is much the same as with running and walking. Simplistic physics says both use the same amount of energy, but you won't get as far by running due to the massive power requirements.
The following is multiple choice question (with options) to answer.
If I wanted to get more energy after exerting myself too much | [
"I can consume an apple",
"I can go for a run",
"I can brush my hair",
"I can wash my face"
] | A | living things all require energy for survival |
OpenBookQA | OpenBookQA-384 | species-identification, ornithology
Why would a mother do that to her young? Does she hates the little one? Not at all. It’s just that those little birds were made to fly, and they don’t know it, so she is going to push them out of the nest. She never lets them hit bottom, but she does let them fall, because they have to learn something they don’t know.
The next time the mother bird comes back she decides to clean house, and so she stands on the edge of the nest. The first things to go are the feathers inside; she drops them over the edge. Then the leaves go over the edge—heave ho! While this is going on, she’s not very talkative, either. ("Mom, what are you doing?") She pays no attention. Since she built the house, she knows how to take it apart.
Next she decides to take the sticks out of the middle of the nest, and with her great strong beak and feet, she’s able to break them off and stand them straight up. ("Mom, it’s not comfortable in here anymore.") Then she takes certain key sticks out of the nest and throws them over the edge. ("What are you doing, Mom? You are wrecking my room.")
She seemingly pays no attention to the concerns of her young as she prepares to pull the nest apart, for she is determined that those little ones will fly, and she knows something they don’t. She knows they will never fly as long as they remain in the nest.
The following is multiple choice question (with options) to answer.
Birds build nests out of things such as | [
"fragments from plants",
"small glass shards",
"entire tree trunks",
"several flower buds"
] | A | a nest is made of branches |
OpenBookQA | OpenBookQA-385 | thermodynamics, thermal-conductivity
Title: Thermal Heat Transfer I work for a large plant bakery and we have recently coated the inside steel walls of our very large oven with a reflective coating. I have taken temperature readings inside the insulation void and there is a noticeable decrease.
What I am trying to do is quantify the theoretical energy savings in LPG usage from this.
It's been quite some years since I ever tried to calculate anything like this and I am in dire need of some guidance. Is Fourier's Law the right direction to be taking with this?
E.G $\dfrac{Q}{T}= \dfrac{KA(T1-T2)}{D}$
$=\text{Thermal conductivity of oven wall} \times \text{surface area of walls}\left(\frac{\text{temp before painting-temp after painting}}{\text{thickness of wall}}\right)$.
Some more background information:
Heat is generated from an LPG burner located centrally in the oven. It is a large swing tray style oven measuring $6$ meters wide by $25$ meters. The reflective coating is a silver heat stable paint on the inside of the oven, before this they were black with carbon. The oven has $2$ steel layers with insulation in between them - temperature readings were taken from inside the insulating cavity.
Thanks in advance In this problem all three modes of heat transfer occur:
radiative
conductive
convective
Firstly, we assume the furnace operates in steady state, so that all heat generated by the LPG burner dissipates away through the furnace's wall. In that case, all temperatures are constant in time.
Also I'll approximate the furnace by a single wall with surface area $A$ and thickness $\Delta x$.
We can write, for steady state:
$$Q_{in}=Q_{out}$$
Now we distinguish $3$ zones, I, II and III:
Left of the $T$-axis is the heat source ($Q$), right the wall with surface area $A$ and thickness $\Delta x$.
Radiative zone (zone I):
The following is multiple choice question (with options) to answer.
A thermal insulator between a stove and a pan would make the pan get hot | [
"slower",
"immediately",
"same speed",
"faster"
] | A | a thermal insulator slows the transfer of heat |
OpenBookQA | OpenBookQA-386 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
The reason raccoons are often found in dumpsters is because they are known to consume | [
"waste",
"caviar",
"cats",
"roses"
] | A | raccoons eat waste |
OpenBookQA | OpenBookQA-387 | thermodynamics, energy, home-experiment
Note 3: Peak hours tend to be during the day (this may reverse if we get wide-spread solar energy), so keeping the house cool during the day would cost even more. You pretty much have it right. We have two scenarios:
1 - Leave air conditioning on all day. Say that outside temperature is 90 degrees and inside temperature is 70 degrees. Then, all day long, the air conditioning has to remove any heat that gets into the house continuously. Heat transfer depends on the difference in temperature between outside and inside the house. In this case, heat transfer per unit time is equal to a constant K times 20 degrees. Over a whole day of D units of time, the total energy removed by the air conditioner is $20KD$ This assumes that convection (ie air draft) can be neglected.
2 - Stop the air conditioning during the day. If you stop the air conditioning, the flow of heat in the house initially will be the same. However, as time goes by, the inside temperature will increase. This will gradually reduce heat flow as it is proportional to the difference in temperatures. If the house is small enough and badly insulated, you could even get to a point where the inside temperature is equal to the outside temperature, at which point no more heat enters the house. When you get back from work, or if you have a timer a bit before, air conditioning is restarted. You now have to remove all the accumulated heat. However, since less heat entered the house over the duration of the day than if you had kept the air conditioning on, you have less work to do to cool down the house. Yes, the heat will have accumulated in insulation, furniture, walls, etc, but it doesn't matter. There is less heat total to remove.
The following is multiple choice question (with options) to answer.
If you desired to keep your house cooler in the summer months | [
"plant trees that tower above the ground",
"plant ivy around the trees",
"plant shrubs around the foundation",
"plant trees that stay smaller than dogwoods"
] | A | large trees block sunlight from reaching the ground |
OpenBookQA | OpenBookQA-388 | visible-light, sun, weather
Title: Why are clouds lighter than the sky during the day but darker at night This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during sunset but apparently it's common in bigger cities).
Basically what I'm wondering is why clouds during the day appear lighter than the sky (white vs light blue) while clouds at night and during the evening appear darker than the sky (see image).
Image quality is low because I took it with my phone through my window.
I guess the clouds could be blocking the light and therefore appear darker but in that case, shouldn't the same thing be happening during the day? There could be quite a few things going on.
Off the bat there's no incoming light for them to scatter: during the day, clouds are white because the water droplets are big enough for all visible light to cause Mie scattering, but if you don't have much light falling on them, you can't observe the scattering and you can't observe light passing through either.
Then you could consider the fact that in some places, it rains more in the evening/night than during the day (if you have hotter surface temperatures during the afternoon, you see cloud formation and precipitation during the late evening, and with the lower temperatures in the night, the air is more likely to become saturated, see Dew Point), and clouds which precede rain are thicker and denser. They don't allow much light pass through.
And lastly, there's less ambient light which they can reflect back towards you.
The following is multiple choice question (with options) to answer.
a cloudy day may obstruct visibility of which of these? | [
"the screen on a smartphone",
"our planet's closest star",
"the teacher in the class",
"the waitress's name tag"
] | B | cloudy means the presence of clouds in the sky |
OpenBookQA | OpenBookQA-389 | zoology, behaviour, mammals, rodents
Title: Why do Guinea Pigs chirp / sing? Ok, so this appears to be quite a mystery. Me and my girlfriend have 2 Guinea Pigs, 1 male and 1 female.
My girlfriend once picked up the female one and took her outside into our garden. The Guinea got scared for some unknown reason and jumped out of my girlfriend's arms and fell down hard.. That night, the female Guinea woke us up with some very strange sounds. She sounded like a chirping bird.
Since then, she sometimes repeats these sounds (most often at night, but not always). Mostly, we are puzzled as to why as there is often no apparent reason for her sounds. Also, when she makes the sounds, she appears to be in a trance-like state, making no movements at all.
Looking for the answer online I found many discussions on the subject like this one or this one. Mostly, the sounds (and the often mentioned trance like behavior) appear to be interpreted as either (1) alarm sounds, (2) loneliness sounds or (3) happiness sounds.
There are also recordings of it one Youtube, like this one.
What I was wondering:
Does anybody know about some actual research that has been committed on this subject? If so, what were the results?
I'm just so very curious to find out! I found this question very interesting so I did some research. Here's a brief summary of what I've found:
Researchers have found that there are 11 different call types. Some of these include a "sharp alarm cry", "sociable clucking", chutter, whining, purring etc. Using body position and behaviour, researchers attempted to associate these vocalizations with behaviour. Some vocalizations had no apparent associated action including what researchers designated the "chirrup" ( I think this is similar to what your guinea pig might have emitted.)
For more information you can read the results section of this paper by Berryman. You can find a full description of each of the 11 calls and their assumed cause or purpose. Some involve social interaction, reproduction, and distress. Much of the research regarding Guinea pig vocalization involves communication and response between mothers and pups.
In short, it seems as though this chirping behaviour your Guinea pig is exhibiting is normal, but not of any known cause.
The following is multiple choice question (with options) to answer.
Billy's new puppy had floppy ears. That might be because | [
"The puppy's mother had ears that looked the same way",
"The puppy was deaf",
"The puppy was tired",
"The puppy was missing the bones in its ears"
] | A | the shape of body parts is an inherited characteristic |
OpenBookQA | OpenBookQA-390 | biochemistry, botany, plant-physiology, photosynthesis, agriculture
The above image is an example of a "potato battery" made without the potato. Identical setup and the energy obtained is identical given everything else the same.
Potato power- er, metal power?
This experiment is supposed to demonstrate the concept of an electrochemical cell. Electrochemical cells obtain their energy from the reduction-oxidation reactions that happen between two metals with different reduction potentials. When two metals - such as copper and zinc - are placed in a medium that permits the exchange of electrons and ions, an electrical gradient is produced as electrons move from one metal to the other and ions move the other direction. This gradient can then be captured and used to do work such as powering a lightbulb or an AI.
In the potato powered example, the power comes from zinc and copper. If you want a more powerful battery, use more zinc and more copper- not a bigger potato. If that is not good enough, try replacing the zinc with something like lithium- this is what we've done with modern, rechargeable batteries.
In truth, the potato battery would be better described as a normal battery that just happens to be inserted into a potato. You'll make a better battery if you use copper pennies and aluminum foil in vinegar.
I do not mean to shoot down your idea, and I am glad you are looking into renewable energy sources- but you may be better served by a class on electricity and batteries than by asking questions on biology.SE!
EDIT: I would assume that the electrical potential of this kind would also kill the plant, given that you're essentially electrocuting it. However, I was unable to find any information on the resistance of potato plants to electrocution.
The following is multiple choice question (with options) to answer.
Materials like ethanol are used to produce electricity by _____. | [
"hydroelectric power",
"renewable energy",
"burning",
"carbon fixation"
] | C | biofuel is used to produce electricity by burning |
OpenBookQA | OpenBookQA-391 | stoichiometry
Title: Calculate water hardness from grams of CaCO3 We have to figure out what the water hardness in mg/L or ppm is for a $\pu{20ml}$ solution of $\pu{0.400M}$ $\ce{CaCl2}$.
We learned that the formula for hardness is mg/L of calcium carbonate per liter. I started by calculating that there would be $\pu{0.801 g}$ of $\ce{CaCO3}$ precipitate if reacted with $\ce{Na2CO3}$. I then converted $\pu{0.801 g}$ to mg and got $\pu{801 mg}$. I finally divides this by the original $\pu{20ml}$ or $\pu{0.02 L}$ but this gives $\pu{40050 mg/L}$ but the correct answer is $\pu{400 mg/L}$.
I feel like I might be making a mistake with units as my answer is 100 times greater than the correct answer but I don't see the problem. Unless I'm missing something, I don't see the problem with your working either. Perhaps check whether you got the original concentration of $\ce{CaCl2}$ given in the problem right (the volume of the solution does not affect your final answer). The given answer may well be wrong, it's irritating but it does happen.
There is one thing I want to comment on though: never round off your answer too early. Since you obtained the intermediate answer of $801 \text{ mg}$, I am assuming you used a precise molar mass for $\ce{CaCO3}$ - I will take this to be $100.09 \text{ g mol}^{-1}$. (If you used the value $100$ you would have obtained $800 \text{ mg}$.) Your calculations should be:
Number of moles of $\ce{CaCO3}$ formed upon addition of excess $\ce{CO3^2-}$
The following is multiple choice question (with options) to answer.
Hardness of minerals may be measured in certain ways, such as what? | [
"heating the minerals to high temperatures",
"applying pressure using a sharp, tough object in order to leave marks",
"hitting the minerals with a tougher stone",
"taking bits of metal and comparing the texture to the minerals"
] | B | measuring the hardness of minerals requires scratching those materials |
OpenBookQA | OpenBookQA-392 | atmosphere, temperature, humidity, atmospheric-optics
Source As described here, condensation of cloud particles (i.e., contrail formation) will occur if the mixing between hot and moist exhaust from an aircraft engine and ambient environmental air results in the mixed air exceeding the ice saturation vapor pressure as its temperature changes. A conceptual diagram of this mixing process is shown here, for exhaust (parcel A) and environmental air (parcel B) with generic temperatures and saturation vapor pressures is shown here:
However, this would require knowledge of these specific temperatures and corresponding saturation vapor pressures. More practically, contrail prediction often just assumes that the air at altitudes where jets typically cruise (commonly, though not always, above 8 km/26,000 ft and at air temperatures below -40°C) is near or above supersaturation with respect to ice. This assumption is used operationally, for example, in NASA's publicly-available persistent contrail forecast. Note that the first source indicates that low wind speeds are also useful in identifying likely regions of persistent contrails.
Several sources of data may be useful in constructing similar analyses or forecasts and comparing to what might be expected on an average day, based on the local climatology. Observational data from radiosondes (i.e., weather balloons with instruments measuring temperature, moisture, and winds) is available globally in near-real time. This provides actual measurements of weather conditions through the relevant altitudes for contrail formation, and is particularly useful if measurements are needed relatively close to a radiosonde launch site.
For broader coverage in both space and time, the US National Oceanic and Atmospheric Administration provides archives of past weather analyses and operational forecast model output that can be requested by the general public. These datasets contain gridded model output with common parameters at various levels through the atmosphere on a national to global scale. While these datasets do not strictly consist of observed measurements, they are useful for analyses extending beyond the relatively limited set of observations available in most circumstances. Output from various operational forecast models is available for near-current or future conditions, whereas the reanalysis datasets provide similar information obtained from model analyses of past weather.
The following is multiple choice question (with options) to answer.
Water vapor condensing in clouds may cause | [
"people to use umbrellas",
"dogs to take a nap",
"rockets to fly to the moon",
"the earth to spin"
] | A | water vapor condensing in clouds causes rain |
OpenBookQA | OpenBookQA-393 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
At any given time on earth, some countries can be in bed and other are in the middle of the day enjoying the outdoors, why? | [
"ocean tides",
"animals",
"planet rotation",
"rotation of sun"
] | C | a planet rotating causes cycles of day and night on that planet |
OpenBookQA | OpenBookQA-394 | morphology, dinosaurs
Title: Based on morphology alone, what type of claw does the Tyrannosaur have? I understand that the exact use of Tyrannosaur Rex's claw is a mystery, or at least debated. I also understand that claws can be used for a variety of different purposes, selective pressure adapts their morphological to be better optimized for certain tasks. Some are used for hunting and killing, like large cats' claws, some are used for digging, like bear's claws, while others are used for climbing, like squirrel's claws.
My question is, all other clues and bits of information about if and how T. Rex might have used its arms, what 'type' of claws did it possess? I'm not asking, in this question, about its arm, the arm's musculature, its mouth or jaw, or about any of the rest of the animal. Based on the morphology of the claw alone, and comparing it to known uses of similarly shaped claws, what types of tasks were the claws geared towards? unfortunately they have fairly generic claws, they are not specialized enough to point to a use. They are curved enough to be used to grasp something but that is true for their ancestral line too so there is no sign of a specific directional selection.
The following is multiple choice question (with options) to answer.
An eagle will use their claws to catch which of the following? | [
"nuts and berries",
"mouse",
"lion",
"elephant"
] | B | claws are used to catch prey by some predators |
OpenBookQA | OpenBookQA-395 | newtonian-mechanics, momentum, acceleration, collision
Title: A problem regarding a fiction Recently I watched a fictional(I guess) video: a man is crossing the road while a truck accelerates towards him and a superhero flashes and saves his life by taking him out of the road. He was very fast, therefore only a flash could be seen. It seems like a silly incident though. After some time the question that occurred in my mind was 'if this happened in reality, could that man survive?'
This is my reasoning:
If the man had to collide with the truck it would create serious damages and this has been explained scientifically in many topics such as energy transferred to the body, force emitted, and so on. Also, I found that the acceleration of the vehicle performs a lower impact on the pedestrian. Nevertheless, everyone knows that more harm is done by a vehicle that goes with $60 \;\text{km/h}$ than $5 \;\text{km/h}$ at a collision. But in this scenario, the speed of the hero is exaggeratedly high(Find the video below). The speed of the truck is negligible in comparison. Thus the impulse on the man is massive when the hero catches him. Can a person endure such a great impulse? I heard that such a great change in momentum will disturb fluids in the person's body and feels extremely uncomfortable. And also can a person tolerate that acceleration? Thus the ridiculous thought that came to my mind was that the damage will be minor when the person had to be hit by the vehicle than is carried by the hero.
This seems to be a silly problem, but I am asking whether this could happen in the real world.
EDIT: Look for video here:- https://youtu.be/KJqhR2YSUXw
The following is multiple choice question (with options) to answer.
A man is burned in an accident on the road, which means that at one point he was | [
"exposed to extreme heat",
"frozen in an ice storm",
"crashed into a helicopter",
"melted by molten lava"
] | A | if a body part was burned then that body part was exposed to a lot of heat energy |
OpenBookQA | OpenBookQA-396 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
Cooking food requires | [
"higher temps to be applied",
"a stove to be used",
"an oven to be used",
"a fire to be built"
] | A | if food is cooked then heat energy is added to that food |
OpenBookQA | OpenBookQA-397 | evolution, ornithology, palaeontology
One thing those many, many bird and proto-bird fossils also made clear is that the traits of modern birds (feathers, wings, toothless beaks, etc) didn't evolve in a simple line from non-bird to bird. Many of those traits evolved convergently in several lineages, were lost in some, maybe regained in others, and feathers in particular turn out to be a widespread dinosaur feature that cannot be considered a uniquely bird trait anymore (unless we want to call T-rexes "birds"). Still, saying "beaks evolved several times" or "feathers evolved several times" doesn't mean that birds, let alone modern birds, evolved from several different ancestors. It can mean that the common ancestor of birds had lots of variously bird-like more-or-less distant cousins living around the same time.
The following is multiple choice question (with options) to answer.
Why would some birds have beaks that look a lot different than those of other birds? | [
"some of the birds eat worms and the other birds have blue feathers",
"some of the birds of the same species have lived in a zoo all their lives",
"some of the birds take seeds for nourishment and the others look for dead animals for nourishment",
"some of the birds like to file down their beaks"
] | C | birds with beaks of different shapes eat different foods |
OpenBookQA | OpenBookQA-398 | image-processing
Title: High Dimensional Spaces for Images Can anyone explain why pictures are not considered 2D, but rather high dimensional? Especially with regards to CV and AI. From one perspective, a picture is a 2D image, because it has height and width.
But from a machine learning perspective, we can think of a picture as a point in a high-dimensional space. In particular, suppose we have a greyscale picture that is $m\times n$ pixels, i.e., $m$ pixels wide and $n$ pixels high. Then there are a total of $mn$ pixels in the image. Each pixel has a greyscale intensity, which we can think of as a real number in the interval $[0,1]$. Therefore, we can think of the picture as being a collection of $mn$ real numbers. In other words, the picture can be treated as a $mn$-dimensional vector -- as an element of $\mathbb{R}^{mn}$. Thus, any particular picture can be thought of as an element of a high-dimensional space.
The latter perspective arises natural for some machine learning approaches to computer vision, e.g., where we feed the pixels of the image into the machine learning algorithm, where each pixel value is treated as a separate pixel.
(A color image can be thought of as an element of $\mathbb{R}^{3mn}$: for each pixel, we have three numbers, corresponding to the intensity in the red, green, and blue channels.)
The following is multiple choice question (with options) to answer.
High can be visually represented by | [
"basins",
"mountains",
"deep sea",
"valleys"
] | B | high means great in altitude |
OpenBookQA | OpenBookQA-399 | biochemistry, microbiology, microbiome
„the higher the potential, the higher the dissolved oxygen in medium“.
I think the wording is misleading, since high redox potential is a consequence of oxygen being present, not the other way around (as that would imply something like high redox potential attracting atmospheric oxygen into water). I speculate that the author meant that dissolved (organic) compounds tend to release $O_2$ (or rather any reactive oxygen species (ROS)) more often in an oxidative milieu.
The following is multiple choice question (with options) to answer.
To positively affect the environment | [
"cut down trees and shrubs",
"drive a gas guzzling car",
"use Styrofoam plates and cups",
"cultivate dogwoods and oaks"
] | D | planting trees has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-400 | wiring
Title: What connectors are most reliable? If you have used connectors for signal wiring for any length of time, you may find that they are unreliable.
Specifically, I find these to be unreliable when used for a long time, with a number of disconnections and re-connections:
This is due to the loss of springy-ness of the crimped metal end on the wire, which causes contact problems.
Which connectors (with rapid connection time) are reliable for multiple re-connections for simple signal wiring?
This excludes screw terminals and connectors with screws (eg. D-subminiature connectors), because they are not simple plug-in connectors. There are lots of very reliable connectors out there. Here are a few of my favorites:
Harwin Datamate These come in a few varieties. The ones shown here are fantastic and have both high current power connections, and many signal connections. They are extremely reliable, and I know that they are used on several robots I know of, including the Shadow Robot Hand, Robonaut and the latest DLR space qualified hand.
The ones you see here are a little on the expensive side, up to $30 each! But the simpler connectors with only signal pins are much more reasonable, just a couple of dollars each. They are extremely reliable. The pins are gold plated and have several contact points. The latching and screw mechanisms on them mean they can even survive the vibration of a rocket launch.
Check out Harwin's other connectors, especially the M30 range. They're pretty small and, if you crimp the wires properly, then they are extremely reliable. I have never seen one of the M30 connectors fail due to repeated mating.
Consumer Connectors: Generally, connectors intended for the consumer market should be able to survive quite a while. These include USB, Firewire, HDMI, VGA, D-Sub.
The other good thing about these connectors is that they are suitable for high speed data, like EtherCAT's LVDS physical layer. The downside of USB, HDMI and Firewire is that they aren't vibration proof, and may fall out if not strapped down. Make sure you get gold plated ones.
Omnetics: The cream of the crop come from Omnetics. They have the double benefits of being both super reliable, and also very small.
The following is multiple choice question (with options) to answer.
What makes the best wiring? | [
"rope",
"Tungsten",
"hemp",
"plastic"
] | B | wiring requires an electrical conductor |
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